.^^^v^Yftv^y^y^^^^ 




LIBRARY OF CONGRESS. 

-i^&-55- 

@(m^ @jjpgng|t T$a.. 

Shelf .«#_!? 



UNITED STATES OF AMERICA. 



THE ESSENTIALS 



OF 



Medical Chemistry 



URINALYSIS. 



is by 

SAM E. WOODY, A. M., M. D., 

PROFESSOR OF CHEMISTRY AND PUBLIC HYGIENE, AND CLINICAL LECTURER ON DISEASES 
OF CHILDREN, IN THE KENTUCKY SCHOOL OF MEDICINE. 

, o / 

THIRD EDITION, Q 

REVISED, EXLARGED AND ILLUSTRATED. 



PHILADELPHIA : 

P. BLAKISTON, SON & CO., 

1012 Walnut Street. 
1890. 




Copyright, 1890, by P. Blakiston, Son & Co. 



PRESS OF WM. F. FELL & CO. 

1220-24 SANSOM STREET, 

PHILADELPHIA. 



PREFACE 



The Third Edition treading so closely on the heels of its prede- 
cessors, assures the writer that his little book has found use in the 
hands of many medical students, and that his labor has lessened 
theirs. 

As long as the effort is made to crowd the whole science of medicine 
into a five months' course, the hurried student must have such a book 
as this to present the essential facts ; so that he need not wade through 
the more exhaustive text-books, or be compelled to take voluminous 
notes, which are unavoidably inaccurate and unsatisfactory. The 
selection of material and the plan of presentation is the outgrowth of 
the author's experience as a general practitioner and as a teacher of 
medical chemistry for the past twelve years. 

The subjects treated are so numerous that the descriptions are 
necessarily brief, but the principles of the science and the application 
of the facts to medicine have been stated more fully. 

1 506 West Walnut Street, 
Louisville, Ky. 



CONTENTS. 



PAGE 

INTRODUCTION, 9 

Table of Elementary Bodies, with their Symbols and Atomic Weights, 12 

PART I.— INORGANIC CHEMISTRY, 15 

Classification of the Elements, 15 

I. Hydrogen and Oxygen Group, 16 

Hydrogen, 16. Oxygen, 17. Compounds of Hydrogen with 
Oxygen — Water, 20. Table of Valence, 27. 

II. The Chlorine Group, 28 

Fluorine, Chlorine, Bromine, Iodine, 28. 

III. The Sulphur Group, 34 

Sulphur, 35. 

IV. The Nitrogen Group, 40 

Nitrogen, 40. The Atmosphere, 41. Phosphorus, 46. 
Arsenic, 49. Antimony, 53. Bismuth, 55. 

V. The Carbon Group, ' . 56 

Carbon, 56. Silicon, 61. Tin, 62. Lead, 63. 

VI. Metals of the Alkalies, 65 

Lithium, 65. Ammonium, 66. Sodium, 67. Potassium, 
68. Gesium and Rubidium, 71. 

VII. Metals of the Alkaline Earths, 71 

Magnesium, 71. Calcium, 73. Strontium, 75. Barium, 75. 

VIII. Metals of the Earths, 75 

Boron, 76. Aluminium, 76. Cerium, 77. 

IX. The Zinc Group, 77 

Zinc, 77. Cadmium, 79. 

X. The Iron Group, 79 

Chromium, 79. Manganese, 80. Iron, 81. Cobalt, 85. 
Nickel, 85. 

vii 



viii CONTENTS. 

PAGE 

XL The Copper Group, 85 

Copper, 85. Mercury, 87. 

XII. The Silver Group, 91 

Silver, 91. Gold, 92. Platinum, 93. 

Table to Determine the Metallic Radical of a Salt, 94 

Table to Determine the Acidulous Radical of a Salt, 95 

Table — The Solubility or Insolubility of Salts in Water, 96 

PART II.— ORGANIC CHEMISTRY, 97 

Hydrocarbons, 98 

Alcohols, 101 

Ethers, 105 

Aldehydes, 108 

Organic Acids, 109 

The Carbohydrates, 112 

Glucosides, 115 

Nitrogenous Bodies, 116 

Alkaloids, 118 

PART III.— THE URINE, 121 

Physical Properties, 122 

Chemical Constituents, 126 

Tests for Albumin, etc., 133 



THE ESSENTIALS OF 

MEDICAL CHEMISTRY. 



INTRODUCTION. 

" Chemistry is that branch of science which treats of the composition 
of substances, their changes in composition and the laws governing 
such changes." {Webster.) 

The distinctive characteristic of chemical action is change in com- 
position* A bar of iron is the same in composition, whether hot or 
cold, luminous or non-luminous, magnetized or unmagnetized. But 
when it undergoes chemical action a new substance is formed which, 
though it contains iron, is entirely different from it in composition and 
properties.! 

Matter is that of which the sensible universe is composed. It is 
indestructible. Substances may undergo many changes, assume a 
great variety of forms, and even become invisible gases. Yet in 
none of these changes and combinations can a particle of matter be 
created or destroyed. J All matter has weight. By balances in the 

* Experiment. — Heat pieces of platinum and magnesium wire. Note that 
while the platinum is unaltered the magnesium burns and is converted into a 
white powder of magnesium oxide. 

•f Experiment. — Weigh a small porcelain crucible containing powdered iron. 
Heat it, and it ignites ; when combustion is complete, weigh again, and note the 
increase of weight and that a new substance is formed, which, though it con- 
tains iron, is not iron. 

J Experiment. — Burn a piece of charcoal (carbon) in a jar of oxygen gas. 
(Fig. I.) It disappears and, so far as we can judge by the senses of sight and 
touch, is lost, for it has combined with the oxygen to form an invisible gas. 
Add lime-water and shake. The gas combines with the lime and forms a 
white precipitate, which, if gathered and weighed, would exactly represent, 
besides the lime, the charcoal burned and the oxygen required to burn it. 



IO 



ESSENTIALS OF CHEMISTRY. 



Fig. 



open air we get the appare7it weight of a body ; but to obtain the abso- 
lute weight it must be weighed in a vacuum 
where there is no air to buoy it up. (For 
measures of weight, see table at back of book.) 
But of most importance to the student of chem- 
istry is the specific weight or specific gravity, by 
which we mean the weight of a substance as 
compared to the weight of an equal volume of 
some other substance specified as a standard. 
The standard for solids and liquids is water ; 
for gases, air or hydrogen. * 

Matter exists in one of three states, solid, 

liquid, or gaseous. In the solid state the particles are held together 




* The specific gravity of solids is determined on the principle of Archimedes : 
A body immersed in a liquid displaces its own volume, and loses weight equal 
to the weight of the liquid displaced. Therefore, the weight a body loses when 
weighed in water, is the weight of its own volume of water and the standard 
with which the weight of that body must be compared, For example, suppose 

A piece of iron weighs 150 grains. 

Suspended in water it weighs 130 grains. 

Loss (or weight of its volume of water) ... 20 grains. 
Specific gravity of the iron (150 -r- 20) . . . 7.5 

In case the body is lighter than water, a sinker is attached and the same 
method pursued, except that the loss of weight of the sinker is also obtained 
separately and subtracted from the total loss to ascertain the loss of weight of 
the lighter body. A body soluble in water may be weighed in some liquid of 
known specific gravity in which it is insoluble; e.g., suppose a lump of sugar 
weighs 100 grains, and in turpentine 45.62 grains. Loss == 100 — 45.62 = 
54.38 grains. 100 -=- 54.38 = 1.84 as the sp. gr. referred to turpentine. 
Multiply this by .87, the sp. gr. of the turpentine, and we get 1.6 
Fig. 2. as the true sp. gr. of sugar. For liquids we use the specific- 

gravity fiask (Fig. 2), which is made and marked to contain a 
certain weight of water. Fill the flask with the liquid to be in- 
vestigated and weigh it. Deduct the weight of the flask and 
divide this result by the weight of water the flask will hold. In 
practice the hydrometer is generally used. This is a hollow glass 
float with a graduated neck at its upper end, which indicates the 
specific gravity by the depth to which it sinks in the liquid. The 
urinometer [the illustration of the urinometer is in Part III, on 
the urine] is a hydrometer whose scale is constructed to measure the specific 
gravity of urine. For very accurate measurements of specific gravity the liquids 
must be at the standard temperature, which in this country is 6o° F. 




INTRODUCTION. 1 1 

so rigidly as to give the body a definite shape ; while in the liquid 
state the attraction is so slight as to allow the particles to move freely 
upon each other and the body to take the shape of the vessel that 
contains it. In the gaseous state the mutual attraction of the parti- 
cles is entirely overcome, and their distance from each other depends 
upon the pressure to which the gas is subjected. The term fluid is 
applied to anything capable of flowing, whether liquid or gaseous. 
It is highly probable that all substances, which are not decomposed 
by heat or cold, are capable of existing in all three states. Heat is 
absorbed and cold produced wherever the particles are to be driven 
farther apart, as in the passage of a substance from the solid to the 
liquid or from the liquid to the gaseous state. 

When the two solids, ice and common salt are mixed, they form a 
liquid, and great cold is produced.* Perspiration in evaporating 
assumes the gaseous state, and absorbs in the change so much heat 
that the body is kept at its normal temperature in spite of the hottest 
weather.f 

On the other hand, when a substance passes from a rarer to a 
denser state it gives out again the heat absorbed in its passage in the 
opposite direction. 

If we examine the infinite variety of substances upon our earth we 
find most of >them are co?nftounds, i. e., they can be decomposed into 
two or more other substances, distinct in their properties from the sub- 
stance from which they were derived and from each other. There 
are some substances which have never been decomposed. These are 
called elements. Only seventy elements are at present known ; but, 
as our methods of investigation improve, this number may be increased 
by the discovery of other elements, or decreased by decomposing 
some of those now considered elements. Only about one-half of 
these enter into the materia medica, and will be noticed in this 
work. 



* Experiment. — Fold tin- foil into the shape of a little dish; add powdered 
ice and salt. Spill water on the table and set the dish in it. Note how quickly 
it is frozen fast to the table. 

| Experiment. — Put a little water in a similar dish. Against the sides and 
bottom throw a spray of ether. Note that the evaporation of the ether is so 
rapid that the water is quickly frozen. 



12 



ESSENTIALS OF CHEMISTRY. 



TABLE OF ELEMENTARY BODIES, WITH THEIR SYMBOLS AND 

ATOMIC WEIGHTS. 

( The more important are Printed in capitals?) 



Name. 



Symbol 



Aluminium, .... 
Antimony (Stibium), 

Arsenic, 

Barium, 

Beryllium, 

Bismuth, 

Boron, 

Bromine, ..... 

Cadmium 

Caesium, 

Calcium, 

Carbon, 

Cerium, 

Chlorine, 

Chromium, .... 

Cobalt, 

Copper (Cuprum), . . 

Didymium, 

Erbium, 

Fluorine, 

Gallium, 

Germanium, .... 
Gold (Aurum), . . . 

Hydrogen, 

Indium, ...... 

Iodine, 

Iridium, 

Iron (Ferrum), . , . 
Lanthanum, .... 
Lead (Plumbum), . . 

Lithium, 

Magnesium, .... 
Manganese, .... 
Mercury (Hydrargy- 
rum), 



Al 

Sb 

As 

Ba 

Be 

Bi 

B 

Br 

Cd 

Cs 

Ca 

C 

Ce 

CI 

Cr 

Co 

Cu 

D 

E 

F 

Ga 

Ge 

Au 

H 

In 

I 

Ir 

Fe 

La 

Pb 

Li 

Mg 

Mn 

Hg 



Atomic 
Weight. 



27 
I20 

75 

m 

9 
208 

11 

80 
112 

*33 

40 

12 
141 

35-5 

52 

59 

634 
145 
166 

19 

70 
163 
197 

1 

1134 
127 
192 
56 

J 39 

207 

7 
24 
54 

200 



Name. 



Symbol 



Molybdenum, .... 

Nickel, 

Niobium, 

Nitrogen, 

Norvvegium, .... 

Osmium, 

Oxygen, 

Palladium, 

Phosphorus, .... 

Platinum, 

Potassium (Kalium), 

Rhodium, 

Rubidium, 

Ruthenium, 

Samarium, 

Scandium, 

Selenium, 

Silicon, 

Silver (Argentum), . 
Sodium (Natrium), , 
Strontium, .... 

Sulphur, 

Tantalum, ..... 
Tellurium, ..... 
Thallium, ..... 
Thorinum, ..... 
Tin (Stannum), . . , 
Titanium, ..... 
Tungsten, or Wolfram, 

Uranium, 

Vanadium, .... 
Ytterbium, .... 

Yttrium, 

Zinc, 

Zirconium, .... 



Mo 

Ni 

Nb 

N 

Ng 

Os 

O 

Pd 

P 

Pt 

K 

Rh 

Rb 

Ru 

Sm 

Sc 

Se 

Si 

Ag 

Na 

Sr 

S 

Ta 

Te 

Tl 

Th 

Sn 

Ti 

W 

u 

V 

Yb 

Y 

Zn 

Zr 



Atomic 
Weight. 



58 

94 

14 
214 
198 

16 
106 

3i 

194.4 

39-1 
104 

85 

104 
150 

44 

79 

28 
108 

23 

87.5 

32 
182 
128 
204 
231 
118 

5o 
184 
240 

51-2 

*73 

90 

65 



To explain the laws governing chemical phenomena we adopt the 
old atomic theory* 



*Democritus, 460 B. a, said: "The atoms are invisible by reason of their 
smallness ; indivisible by reason of their solidity; impenetrable and unalterable." 



INTRODUCTION. 1 3 

We will take up the theories and laws, not in the order of their 
enunciation, but of their natural sequence. 

It is assumed that matter is composed ultimately of infinitely small 
particles called atoms ; that each element is composed of atoms, all 
of a certain size, weight, etc. Atoms do not exist alone, but in groups 
called molecules. In an element the molecule is composed of pairs 
of atoms of the same kind ; in compounds they consist of two or more 
atoms of different kinds. It has been determined that equal volumes 
of all substances in the gaseous state, and under like conditions, con- 
tain the same number of molecules. So a gallon of hydrogen gas 
and one of oxygen gas containing the same number of molecules, 
and those molecules consisting of pairs of atoms, must contain the 
same number of atoms. Furthermore, it is found that the gallon of 
oxygen is sixteen times as heavy as the gallon of hydrogen. So each 
oxygen atom must also be sixteen times as heavy as the hydrogen 
atom. Hydrogen being the lightest substance known, its atomic 
weight \s taken as I, and consequently the atomic weight of oxygen 
is 1 6. The atomic weights of other elements are determined in a 
similar way. By "atomic weight" is not meant the absolute weight 
of atoms (for that is not known), but the weight of the atom as com- 
pared to the hydrogen atom. The atomic weight of carbon is 12. 
If carbon combines with oxygen, atom for atom, the new substance 
(CO) resulting from that action will consist of molecules, in each of 
which the carbon will weigh 12 and the oxygen 16, and, as the whole 
mass is composed of these molecules, the same proportion obtains 
throughout the new compound. So 12 is found to be the combining 
weight of carbon, and 16 of oxygen. If, however, the combination 
should occur in the proportion of one atom of carbon to two atoms of 
oxygen, then each molecule must consist of 12 by weight of carbon 
to 32 of oxygen, and that must be the proportion throughout the 
entire substance. 

Between these two compounds no intermediate one can occur, for 
the carbon atom must take one or two, or more, oxygen atoms. It 
cannot take a fraction of one, for atoms are indivisible. Hence, we 
deduce the following Law : Substances combi7ie in certain fixed pro- 
portions (atomic weights), or in multiples of these proportions. 

Symbols are abbreviations of the names of the elements. They 
consist of the initial letter of the Latin name ; but if the names of 
several elements begin with the same letter, the single-letter symbol 



14 ESSENTIALS OF CHEMISTRY. 

is reserved for the most common element, and for the others another 
letter is added. Thus, we have nine elements whose names begin 
with C ; the most common is carbon, whose symbol is C ; the others 
add other letters, as chlorine, CI ; cobalt, Co ; copper (cuprum), Cu, 
etc. The symbol indicates just one atom. When more than one 
atom is to be represented, the number is written just after and below 
the symbol, thus, Q. • 

Formula are to molecules what symbols are to elements. They 
indicate the kind and number of atoms composing the molecule. 
When more than one molecule is to be indicated, the number is 
placed in front of the formula, thus, 5H 2 0. A parenthesis inclos- 
ing several symbols or formulae should be treated as a single symbol, 
thus, 2(NH 4 ) 2 C0 3 = N 4 H 16 C 2 6 . 

An equation is a combination of formulae and algebraic signs to 
indicate a chemical reaction and its results. As no matter is ever 
lost or created in a reaction, the number of each kind of atoms before 
the equality sign must be the same as after it. 



PART I.— INORGANIC CHEMISTRY. 



Classification of the Elements. — The elements are usually 
divided into two great classes : {a) Metals, about fifty-five in number, 
possessing a peculiar lustre, good conductors of heat and electricity, 
and whose oxides when combined with water form bases ; (J?) Non- 
metals, about fifteen in number, possessing little lustre, poor conduct- 
ors of heat and electricity, and whose oxides combine with water 
to form acids. A better classification, and the one we shall adopt, is 
the following, based upon chemical properties : — 

I. The Hydrogen and Oxygen Group. 
II. The Chlorine Group : Fluorine, Chlorine, Bromine, Iodine. 

III. The Sulphur Group: (Oxygen) Sulphur, Selenium, Tellu- 
rium. 

IV. The Nitrogen Group : Nitrogen, Phosphorus, Arsenic, An- 
timony, Bismuth. 

V. The Carbon Group : Carbon, Silicon, Tin and Lead. 

VI. The Alkaline Group : Lithium, Ammonium, Sodium, Potas- 
sium, Rubidium and Caesium. 

VII. The Alkaline Earths Group: Magnesium, Calcium, 
Strontium, Barium. 

VIII. The Earths Group : Boron, Aluminium, Lanthanum, Ce- 
rium, Didymium, etc. 

IX. The Zinc Group : Zinc, Cadmium. 

X. The Iron Group : Chromium, Manganese, Iron, Cobalt, 
Nickel. 

XL The Copper Group : Copper, Mercury. 

XII. The Silver Group: Silver, Gold, Platinum. 

'5 



i6 



ESSENTIALS OF CHEMISTRY, 



I. Hydrogen and Oxygen Group. 

In a strict arrangement hydrogen would be placed in Group I of the 
metals and oxygen in the sulphur group. But we will consider them 
in a group to themselves, because (a) of all the elements hydrogen is 
taken as the standard for atomic weights, combining weights, valence, 
etc. ; (&) oxygen plays a most important role in chemistry, and its 
deportment with the other elements forms the basis of our classifi- 
cation ; (c) the chemistry of these two will best serve as an introduc- 
tion to the studv of the other elements. 



Fig. 3. 




HYDROGEN (H — 1) occurs free in volcanoes, gas wells, etc. ; com- 
bined in water and all organized bodies. All acids are salts of 
hydrogen. Prepared in various ways from its compounds,* the most 
convenient being to displace it from sulphuric acid by zinc, thus — 

H 2 S0 4 + Zn = ZnS0 4 + H 2 . (Fig. 3.) 

Physical Properties. — Transparent, colorless, odorless, tasteless gas ; 
the lightest substance known, fourteen and a half times as light as 
air ; hence used in balloons. Long suspected to be a metal, because 
it displaces metals in chemical compounds, forms alloys with certain 

* Experiment. — By means of a wire gauze spoon hold some sodium beneath 
the water and under a cylinder. The hydrogen gas liberated by the sodium 
from the water will rise in bubbles, fill the cylinder, and displace the water. 



PART I. — INORGANIC CHEMISTRY. 



17 



metals, and conducts electricity. This was proved in 1877, when 
Pictet condensed it under great cold and enormous pressure into a 
bluish metallic liquid. 

Chemical Properties. — Hydrogen does not support ordinary com- 
bustion or animal respiration. It burns in air with a pale but very 
hot flame.*! With pure oxygen it forms the oxyhydrogen flame. 
This is the hottest flame known, and a stick of lime held in it glows 
with dazzling brilliancy, forming the calcium or Drummond light. 
Mixed with air or oxygen, it explodes violently on contact with a 
spark. J 

Fig. 4. 




OXYGEN (O — 16). — Sources. Most abundant of the elements, com- 
prising one-fifth of the air, eight-ninths of water, one-half of the crust 
of the earth, and three-fourths of all organized bodies. Prepared 
most easily by heating potassium chlorate (Fig. 4) : — 

KC10 3 = KC1 + 3 . 



* Experiment. — If an inverted jar of the gas is suddenly turned up, and a 
flame held a foot or two above, the gas escaping from the jar rises rapidly, and 
in coming in contact with the flame burns with a slight explosion. 

f Experiment. — If a jar of the gas be held mouth down and a candle be 
passed up into it, the gas ignites and burns quietly at the open end, while the 
candle passed up into the gas is extinguished, but may be relighted again by 
the burning gas as it is withdrawn. 

% Experiment. — Fill a bladder or rubber bag with two parts of hydrogen 
and one of oxygen or five of air. Attach a tube and blow up soap bubbles in a 
basin. Touched with a flame, they explode. 



ESSENTIALS OF CHEMISTRY. 



If manganese dioxide (Mn0 2 ) be mixed with the chlorate, the gas 
is liberated more quietly and at a lower temperature. The manga- 
nese dioxide is unaltered in the reaction. It seems to act by its mere 
presence, an influence called catalysis. 

Physical Properties. — Gas ; liquefied (Pictet, 1877) by great cold and 
intense pressure; colorless, odorless, tasteless; 1.10 times as heavy 
as air. Water dissolves only three volumes to the hundred, but 
enough to sustain aquatic life. 

Chemical Properties. — Intense affinities ; combines with every 
element except fluorine. The product of its action is called an oxide, 
and the process oxidation. Oxidation so rapid as to produce heat 
and light is called combustion ; if no light, slow combustion. Sub- 
stances that burn in air burn more brilliantly in oxygen,* and many 
substances that do not burn in air will burn in this gas.f By this 
property oxygen is usually recognized and 
distinguished from most other gases. Oxy- 
gen, especially in its diluted form (air), is 
the great supporter of combustion, for which 
its abundance and universal presence emi- 
nently fit it. Combustible and supporter of 
combustion are only relative terms. When 
a combustible substance burns in a sup- 
porter of combustion the union is mutual, 
one being as much a party to the action as 
the other. A jet of air t or oxygen burns as 
readily in coal gas as a jet of coal gas burns in air or oxygen. The 



Fig. 5. 




* Experiment. — A bit of phosphorus, dried by pressing between folds of 
blotting paper, is placed in a combustion spoon, ignited, and lowered into a jar 
of oxygen. The combustion is so intense that the phosphorus volatilizes, and 
its vapor burns throughout the jar with a brilliancy so dazzling that it is called 
the " phosphorus sun." 

I Experiment. — A watch-spring is wound into a spiral, tipped with a bit 
of tinder or a piece of yarn dipped in sulphur. This is lighted and lowered into 
a jar of oxygen. (Fig. 5.) The iron catches fire and burns with brilliant 
scintillations, globules of melted iron falling and melting into the glass, unless 
the bottom be covered w T ith sand or water. 

% Experiment. — Secure an ordinary lamp chimney (Fig. 6) and a wide cork 
to fit its lower end. Pass through the cork a narrow tube [a) connected by 
rubber hose with the house gas, and a wider one opening into the air. Turn 



FART I. — INORGANIC CHEMISTRY. 



*9 



Fig. 6. 



one in greatest abundance is usually called the supporter of combus- 
tion. 

Oxidizing agents are compounds in which oxygen is held so feebly 
it is readily given up to substances having greater affinity for it. 

Uses. — The process of respiration is a species of combustion, and, 
as oxygen is the best supporter of combustion, it is the best (and only) 
supporter of animal respiration. Admin- 
istered in capillary bronchitis, oedema 
glottidis, etc., when the patient cannot 
take in a volume of air sufficient to supply 
the requisite amount of oxygen. 

Ozone. — If through a portion of air or 
oxygen electric sparks be passed,* a part 
of the oxygen will acquire a pungent odor 
and peculiar properties. The same change 
may be induced by various chemical pro- 
cesses, e. g. by mixing permanganate of 
potassium and sulphuric acid, or when 
phosphorus partially covered with water 
is exposed to the air. This modified 
oxygen is called ozone. It is one and a 
half times as heavy as ordinary oxygen, 
for its molecule contains three instead of 
two atoms. Very energetic, oxidizing 
substances unaffected by ordinary oxy- 
gen. Oxidizes potassium iodide with 




on the coal gas and light it as it issues from the tube. The cork with the 
flame (not too large) is then inserted into the chimney, where it continues to 
burn, sufficient air entering through the wide tube (<:). Upon turning on more 
gas the air is crowded out and the chimney filled with coal gas. The gas flame 
disappears from the tube (a), and an air flame appears upon the tube (c) as the 
entering air burns in the atmosphere of coal gas. The excess of coal gas may 
also be lighted as it escapes, showing a gas flame above and an air flame within 
the chimney. On lessening the flow of gas the air will again be in excess, and 
the flame again appear on the narrow tube (#). In the gas flame above the 
lamp chimney (Fig. 6) heat some potassium chlorate in a combustion spoon 
until it melts and oxygen begins to bubble up. Then lower it into the atmos- 
phere of coal gas within the chimney. The escaping oxygen burns brilliantly, 
the coal gas being the supporter of the combustion. 

* Siemens' apparatus for ozoning oxygen (Fig. 7) consists of two tubes, the 
inner surface of the inner and the outer surface of the outer tube being coated 



ESSENTIALS OF CHEMISTRY. 



liberation of iodine, hence its test: paper dipped in a solution of 
potassium iodide and starch is colored blue in the presence of ozone* 
Ozone is found in the air, especially after thunder-storms, and when 
present in considerable amount (as much as .00005 per cent.) is apt 
to irritate the respiratory tract ; but by oxidizing infecting germs, etc., 
it prevents the spread of infectious diseases. 

Compounds of Hydrogen with Oxygen.— Two are known- 
hydrogen oxide, or water, H 2 0; hydrogen peroxide, or oxygenated 
water, H 2 2 . 

Water (H 2 0) occurs widely distributed in nature ; an important 



Fig. 



constituent of all organized tissues ; forms seven-eighths of the human 
body. 

Physical Properties.— Transparent, colorless, odorless, tasteless- 
liquid. Below 32 F. (o° C.) it is a solid (ice), and above 212 F. 
(100 C.) a vapor (steam or water gas). In solidifying, water expands ; 
so ice floats. The boiling-point is higher than 212 F. under increased 
pressure or when it contains solid matter in solution. 



with tin-foil, and each connected with the poles of an induction coil or Toepler- 
Holtz machine. A current of oxygen passing between these tubes may be 
ozonized to the extent of fifteen or twenty per cent. 

m * Experiment.— Pour a little ether into a beaker, across the top of which 
is a glass rod supporting a strip of blue litmus paper and one of paper dipped 



PART I. — INORGANIC CHEMISTRY. 



21 



Fig. 8. 



Water is the greatest of all solvents. The watery solution of a 
fixed substance is called a "liquor" and of a volatile substance an 
" aqua" 

One body is said to dissolve in another when they coalesce and their 
particles intimately mingle. This is possible only in the liquid and 
gaseous states. When a substance dissolves it takes on the physical 
state of the solvent, e.g., a solid or gas dissolving in water becomes a 
liquid and then mixes with the water, the gas elevating the temperature 
and the solid lowering it. Heat assisting the 
liquefaction of a solid, and opposing that of a 
gas, hastens the solution of the one and retards 
that of the other. Most solid substances when 
separating from a solution take with them, as 
a necessary part of the crystal, a certain definite 
amount of water — water of crystallizatioii . This 
water does not modify the chemical nature of 
the substance, but is necessary for maintaining 
the crystalline form. If the crystal loses its 
water of crystallization by heat or exposure, it 
effloresces into an amorphous powder. Some 
substances when exposed absorb water from the 
air and deliqitesce (melt down). 

Chemical Properties. — The chemical composition of water may be 
proved by {synthesis} combining its constituents (H 2 + O = H 2 0) * or 
by (analysis) passing the galvanic current through water until it is 
decomposed into its component gases (H 2 = H 2 + O). f Neutral in 
reaction ; combines with the oxides of the metals to form hydrates 
(bases), and with the oxides of the non-metals to form acids. 

Natural waters are never pure. The nature of the impurities in 




in potassium iodide and starch- water. Hold a hot glass rod in the jar (Fig. 8) ; 
the ether will undergo slow combustion, producing acid fumes which redden 
the litmus, and ozone which blues the other paper. 

* A mixture of two volumes of hydrogen and one of oxygen exploded in a 
eudiometer (Fig. 9), produces only water. 

f Fill the apparatus shown in Fig. 10 with water acidulated with sulphuric 
acid. Connect with a battery. The electricity passing through the water 
decomposes it into two volumes of hydrogen which collects in one tube and 
one volume of oxygen in the other. 



22 



ESSENTIALS OF CHEMISTRY. 



water depends on the condition of the atmosphere through which it 
has fallen as rain, and the nature of the geological strata through or 
over which it has passed, for water dissolves something from almost 
everything it touches. Good, potable (drinkable) water should be cool, 
clear and odorless. It should contain just enough dissolved gases 
and solids to give it an agreeable taste, neither flat, salty, nor sweetish ; 
and should dissolve soap without forming a curd. Water impregnated 



Fig. 9. 





with inorganic matters, especially salts of calcium, is called hard. A 
much more serious contamination is with organic (animal and vege- 
table) matters. Such water is a prolific source of diease. It is 
probable, in fact almost proven, that most infectious diseases are due 
to microorganisms, many of which find the most favorable conditions 
for their life and growth in water contaminated with organic, especially 
animal, matter. Though chemical analysis cannot detect the disease- 
producing elements, it can detect organic impurity, without which they 



PART I. — INORGANIC CHEMISTRY. 



23 



cannot exist. This is easily done thus: (1) Half fill a clean bottle 
with the water, warm, agitate, and critically smell it. A foul odor 
indicates organic impurity. (2) Fill a clean pint bottle three-fourths 
full, add a teaspoonful of the purest white sugar or gelatin ; set aside 
in a warm place for two days, when, if it becomes cloudy (bacteria), 
it is unfit to use. These rough-and-ready tests are those best suited 
to the practitioner, the more exact methods being practicable only to 
the chemist. 

To pttrify natural waters, they may be boiled to kill living organ- 
isms, and filtered to remove suspended matters ; but for chemical 

Fig. 11. 




purposes, where great purity is desired, they are distilled* {aqua 
destillata, U. S. P.). 

Mineral waters are those possessing special therapeutic value. 
They may be classed as follows : — 

1. Carbonated, those charged with carbonic acid. 



* When a liquid is rapidly vaporized, and the vapor, passing through a 
colder vessel, is recondensed, the process is called distillation (Fig. 11). If 
a solid be similarly treated it is called sublimation. When water containing 
solid matter in solution is distilled, the solids remain in the vessel, while the 
water passes over, enabling us to obtain perfectly pure water. When a mixture 
of two or more liquids is heated, the one having the lowest boiling-point 
distills first, leaving the others behind. This is called fractional distillation. 



24 ESSENTIALS OF CHEMISTRY. 

2. Sulphur, containing H 2 S or some soluble sulphide. 

3. Alkaline, containing alkaline salts of potassium, sodium, or 
lithium. 

4. Saline, containing neutral salts. 

5. Chalybeate, containing iron. 

6. Thermal, or hot waters. 

Hydrogen Dioxide — Oxygenated Water (H 2 2 ). — Prepared most 
easily diluted by passing C0 2 through water holding barium dioxide 
in suspension. 

Ba0 2 + C0 2 + H 2 = BaC0 3 + H 2 2 . 

The BaC0 3 may be allowed to subside and the clear solution poured 
off. 

Properties. — When concentrated it is a colorless, syrupy liquid, with 
a pungent odor and taste — prone to decompose into H 2 + O. 

Used to bleach* the hair and skin, converting brunettes into 
blondes ; as a disinfectant to ulcers, ozsena, and in diphtheria, espe- 
cially when the membrane has invaded the nose ; also as a test for 
pus in urine, with which it causes an effervescence. 

The so-called " ozonized ether " used in the guaiacum test for blood 
is a mixture of hydrogen peroxide and ether. 

RADICALS. — Every molecule is composed of two parts, called 
radicals, held together by chemical affinity. Both radicals may be 
elements, as in H — CI, or one may be elementary and the other 
compound, as H — N0 3 , or both compound, as NH 4 — N0 3 . Some 
compound radicals can be isolated, e. g. by heat, Hg — CN = Hg 
+ CN. Others decompose whenever set free. Whenever a gal- 
vanic current is passed through a compound, the chemical affinity 
is overcome by the electricity, and the molecule separates into its 
two radicals, one of which goes to the positive and the other to the 
negative pole.f Unlike electrical conditions attract, so the radical 

* Experiment. — Secure an old oil painting darkened with age, or take 
paper dipped in lead acetate and blackened by hydrogen sulphide : wash it 
with hydrogen dioxide, and the dark stain will be made white by the lead sul- 
phide being oxidized into sulphate. 

f Experiment. — Into a jar put some water ; add solutions of red litmus, 
potassium iodide, and boiled starch; connect with the galvanic battery. The 
electric current decomposes the potassium iodide into iodine, which gathers at 
the positive pole, producing a blue color, with the starch, and potasshim at 
the negative, where it produces alkali, turning the red litmus blue. 



PART I. — INORGANIC CHEMISTRY. 25 

going to the negative pole must be electro-positive, and the one going 
to the positive pole electro-negative. The metallic radicals are usually 
electro-positive and the non-metallic electro-negative. 

Some radicals are more intensely electro -negative or electro-positive 
than others. In the following list the more common elements are so 
arranged that each is usually positive to those following it and nega- 
tive to those preceding : — 

Positive end : + K, Na, Mg, Zn, Fe, Al, Pb, Sn, Bi, Cu, Ag, Hg, 

Pt, Au, H, Sb, As, C, P, S, N, T, Br, CI, F, O— Negative end. 

A radical is electro-positive or electro-negative only in its relation 
toother radicals ; for, while C is positive to O, it is negative to K. 

In formulae the electro-positive radical is written first and the 
electro-negative next. 

The greater the difference between the electrical condition of two 
radicals, the greater the energy with which they unite and the more 
stable the product, and, vice versa ; e. g., O has a strong affinity for K, 
a weak one for CI, and will not unite with F under any circum- 
stances. An idea once prevailed that the relations of affinities were 
fixed and constant between the same substances, and great pains 
were taken to construct tables similar to the above to show what was 
called the " precedence of chemical affinities." These tables showed 
the order of affinities for the circumstances under which the experi- 
ments were made, and nothing else. 

The circumstances attending chemical reactions are so complicated 
that in the greater number of cases it is impossible to predict the pre- 
cedence of affinities and the result of an untried experiment. 

Among these modifying causes may be mentioned : — 

1. Temperature, changes of which often reverse chemical affinities. 
Moderately heated, mercury and oxygen will readily combine, but 
when highly heated their affinity is destroyed, and they will refuse to 
unite, or, if already combined, will separate. 

Ordinarily free carbon has no affinity for oxygen, but at high tem- 
peratures it surpasses all other elements in its greediness for that 
substance, even taking it from a metal so extremely electro-positive 
as potassium. 

2. Volatility. — Whenever in a mixture of two or more substances it 
is possible, by a rearrangement of the radicals, to form a compound 

3 



26 ESSENTIALS OF CHEMISTRY. 

volatile at the temperature of the experiment, such rearrangement will 
occtcr and the volatile compound be f owned. For example : — 

Fe S + H 2 SO^ = Fe S0 4 + H 2 S ; or, 
2 NH 4 CI + Ca C0 3 = (NH 4 ) 2 C0 3 + Ca Cl 2 ; or, 
H 3 B0 3 + 3 Na CI = 3 H CI + Na 3 B0 3 . 

3. Insolubility. — Whenever, on mixing two or more substances in 
solution, it is possible, by rearrangement of the radicals, to form an 
insoluble compoicnd, that rearrangement will occur and the insoluble 
compotmd be formed as a precipitate. For example : — 

Ca Cl 2 + (NH 4 ) 2 C0 3 = Ca C0 3 + 2 NH 4 CI. 

It is especially important to remember this law, for its application in 
tests, incompatibilities, and antidotes. 

4. Nascent State. — Ordinarily the atoms of an element are grouped 
in pairs, and hence somewhat indifferent to the attractions of other 
atoms ; but just as they are being liberated (born) from a compound 
they are alone. Each atom, having no fellow, readily enters into 
combination with any atom it meets. This state is called nascent 
(nasci, to be born). 

5. Catalysis. — This is the name given to the unexplained influence 
exerted by some substances of inducing chemical reactions between 
other substances without itself undergoing any change. 

The valence of a radical is its combining value, or its value in ex- 
change for other radicals.* Here again hydrogen is taken as the 
standard. A radical that combines with or takes the place of one 
atom of hydrogen is said to be ti7uvale?it (one valued) ; of two atoms, 
bivalent ; three, trivalent ; four, quadrivalent ; five, quinquivalent ; 
six, sexivalent. The valence is indicated by a Roman numeral just 
above and after the radical, thus : (NH/), Ca 11 , (P0 4 ) m , Si IV , As v , S VI . 
The two radicals of every saturated compound must possess an equal 
number of unsatisfied valences. Hence, 

In HC1 the radical CI is equivalent to 1 atom of hydrogen; 

In H 2 the radical O is equivalent to 2 atoms of hydrogen ; 

In NH 3 the radical N is equivalent to 3 atoms of hydrogen ; 

In CH 4 the radical C is equivalent to 4 atoms of hydrogen. 

* The student should bear in mind that valence has nothing to do with the 
combining weight or the chemical activity of an element. 



PART I. — INORGANIC CHEMISTRY. 



27 



Therefore CI is univalent, O bivalent, N trivalent, and C quadriva- 
lent. 

The same regard for valence is observed when radicals are made 
to displace each other, thus : H I 2 (S0 4 ) n requires two atoms of K 1 or 
one of Zn 11 to form K T 2 (S0 4 ) n or Zn u (SO;) n . 

Some elements exercise more than one valence : e.g., mercury may 
be univalent, as in Hgl, or bivalent, as in HgL ; or iron may be biva- 
lent, as in FeCL, or the double atom (Fe 2 ) sexivalent, as in Fe 2 Cl 6 . 
The termination "ous" is given to those compounds in which the 
positive element exercises its lower valence, and "ic" to those in 
which the higher valence is exercised, as, FeCl 2 , ferrous chloride ; and 
Fe 2 Cl 6 , ferric chloride. 

In the following table the most commonly occurring simple or ele- 
mentary radicals are arranged according to their valence : — 

Table of Valence. 



I 


II 


Ill 


IV 


V 


VI 


F, CI 


Ba, Sr 

Ca, Mg 

Cd, Zn 

O 


Al 


C, Si 

Pt 


N, P ! 

Bi, Sb, As.. 




Br, I 


Au 




H,A g 


Bo 


Pb, Sn 




N, p"! 

Bi, Sb, As .. 




K, Na 

(NHJ,Li.. 


Pb,Sn 

S, Se 

Fe, Cr 

Mn, Co 

Ni 


S, Se" 
Fe 2 , Cr 2 
Mn 2 , Co 2 

Ni 2 


Cu,Hg 


Cu,Hg 





The next table shows the valences, together with the symbols and 
formulae, of the most common electro-negative (acidulous) radicals : — 

CI is the negative radical of all chlorides. 

Br is the negative radical of all bromides. 

I is the negative radical of all iodides. 

CN is the negative radical of all cyanides. 

HO is the negative radical of all hydrates. 

N0 3 is the negative radical of all nitrates. 

CIO3 is the negative radical of all chlorates. 

C 2 H 3 2 is the negative radical of all acetates (Ac). 



28 



ESSENTIALS OF CHEMISTRY. 



O is the negative radical of all oxides. 
S is the negative radical of all sulphides. 
S0 3 is the negative radical of all sulphites. 
S(\ is the negative radical of all sulphates. 
C0 3 is the negative radical of all carbonates. 
C 2 4 is the negative radical of all oxalates (Ox.). 
C 4 H 4 6 is the negative radical of all tartrates (T.). 

%m f C 6 H 5 7 is the negative radical of all citrates (Cit.). 
rt.H -j P0 4 is the negative radical of all phosphates. 
£ £ I B0 3 is the negative radical of all borates. 

The student should learn these tables thoroughly, for with them he 
can easily know the formulae of all the principal inorganic and organic 
compounds. 

Fig. i2. 




II. The Chlorine Group. 



Name. 


Derivation of Name. 


Symbol. 


At. Wt. 


Fluorine, 


Fluor spar, 


F, 


19 


Chlorine, 


X^poq, green, 


CI, 


35-5 


Bromine, 


Bpcbjuog, stink, 


Br, 


80 


Iodine, 


ludrjq, violet, 


I, 


127 



The members of this group are all univalent and much alike in 
their sources and physical and chemical properties. They differ in 
degree rather than in kind, forming a graded series. Hence we will 
consider them all together. 



PART I. — INORGANIC CHEMISTRY. 29 

Sources. — Never free in nature. The principal source of fluorine 
is fluor spar (CaF 2 ), while compounds of chlorine, bromine and iodine 
are abundant in sea and other salt waters. 

Preparation. — Free fluorine is obtained only with great difficulty ; 
the others may be prepared by removing the hydrogen from their 
hydrogen salts (hydracids) by means of oxygen derived from manga- 
nese dioxide, thus : — 

4HCI + Mn0 2 = MnCl 2 + 2H 2 + Cl 2 * 
4HBr + Mn0 2 = MnBr 2 + 2H 2 + Br 2 . 
4HI + Mn0 2 = Mnl 2 + 2H 2 + I 2 . 

Physical Properties. — Fluorine is a colorless gas, with properties 
resembling chlorine, but more intense. Chlorine is a -very irritating 
yellowish-green gas, two and a half times as heavy as air, slightly 
soluble in water (three volumes), forming "Aqua chlori y U. S. " 
Bromine is a red liquid, giving off red vapors of a disagreeable, 
irritating odor ; very slightly soluble in water. 

Iodine is a solid, in bluish-gray scales, which, when warmed, give 
off violet vapors ; insoluble in water except by the intervention of an 
alkaline iodide; f soluble in alcohol; irritating, even caustic. 

Chemical Properties. — Intensely electro-negative ; great affinity for 
the metals, J especially hydrogen. § In negativeness, and conse- 
quently in affinity for the metals, F is greatest, CI next, Br next, 
and I least. Therefore, in compounds with the metals, F will displace 



* Experiment. — Into a flask standing in a cup of sand over a heater (Fig. 
12) pour several ounces of hydrochloric acid and half as much black oxide of 
manganese, and agitate. The gas passes out, and, being heavier than air, 
collects in the bottle, where its yellowish-green color makes it visible. 

f Experiment. — To some water in a test-tube add a few scales of iodine ; 
it does not dissolve. Now add a crystal of potassium iodide; it dissolves 
easily. 

% Experiment. — Into a jar of chlorine introduce some copper or bronze 
foil, or sprinkle some powdered antimony. They inflame spontaneously. 

\ Experiment. — [a) Into a jar of chlorine lower a lighted candle. The 
hydrogen of the tallow burns in the chlorine to form hydrochloric acid, and 
all the carbon is liberated as smoke. (/;) Into a similar jar thrust a piece of 
paper dipped in warm turpentine. It inflames spontaneously and burns, evolv- 
ing dense clouds of smoke. 



30 ESSENTIALS OF CHEMISTRY. 

CI, and CI will displace Br, and either F, CI, or Br will displace I.* 
These elements destroy coloring matters and noxious effluvia in two 
ways: (i) by abstracting their hydrogen; (2) by abstracting the 
hydrogen of water, setting free nascent oxygen, which oxidizes the 
matters in question. f 

Medical. — Chlorine gas and bromine vapor are used for disinfec- 
tion. Inhaled they cause severe coryza and bronchitis. Taken into 
the stomach, bromine and iodine cause gastro-enteritis. The antidote 
is boiled starch. Locally bromine is used as an escharotic and iodine 
as a counter-irritant. 

Pharmaceutical. — The following preparations are officinal : Tinc- 
tura Iodi (Sj-Oj) ; and Liquor Iodi Compositus (Lugol's Solution) 
(Iodine 3yj, potassium iodide §iss, and water Oj.) The so-called 
colorless tincture of iodine is made by adding ammonia-water to the 
tincture until it is decolorized by converting the iodine into ammo- 
nium iodide. 

Tests. — In the free state chlorine and bromine may be known by 
their bleaching, color, odor, etc. Iodine is recognized by the blue 
color it strikes with starch. 

Note. — Acids. — All acids have, as their (positive) basylous radical, 
hydrogen, which maybe replaced by metals to form salts. They may 
generally be recognized by a sour taste and the property of turning 
vegetable blues (e.g., litmus or purple cabbage) to reds. Acids whose 
acidulous (negative) radicals contain oxygen are called oxacids; 
those containing no oxygen, hyd7'acids. The members of the chlo- 
rine group form both classes of acids., 



* Experiment. — Take two large test-tubes half full of water. Into one put 
a grain of potassium bromide, into the other potassium iodide ; add chlorine- 
water to each. The chlorine will liberate the bromine in one and the iodine 
in the other. This may be shown (a) by their color ; (7>) by adding a few 
drops of carbon bisulphide or chloroform, which on agitation will gather all 
the free bromine and iodine, and be colored brown with the one and violet 
with the other ; (c) add a few drops of starch-water, which will give brown 
with bromine and a deep blue with iodine. 

f Experiment. — (a) Into one bottle of chlorine gas introduce a piece of 
dry calico, into another a moist piece. The moist calico is rapidly bleached, 
while the dry is but slowly affected, (b) To a solution of indigo, cochineal, 
or some aniline color add chlorine- water. It is immediately decolorized. 



PART I. — INORGANIC CHEMISTRY. 3 1 

The Hydracids of the chlorine group are as follows : — 

H -f F = HF — Hydrogen Fluoride* — Hydrofluoric acid. 

H + CI = HC1 — Hydrogen Chloride — Hydrochloric (muriatic) acid. 

H -f- Br = HBr — Hydrogen Bromide — Hydrobromic acid. 

H -f I = HI — Hydrogen Todide — Hydriodic acid. 



Fig. 




Prepared 'by treating the appropriate salt with H 2 S0 4 , thus : 

CaF 2 + H 2 S0 4 = CaS0 4 + 2HF. 
2NaCl + H 2 S0 4 == Na 2 S0 4 + 2HCl.f 
2KBr + H 2 S0 4 = K 2 S0 4 + 2HBr. 
2KI + H 2 S0 4 = K 2 S0 4 + 2HI. 



* Binary compounds — i. e., those of only two elements — are named by call- 
ing first the name of the positive and then that of the negative radical, affixing 
to the latter the termination " ide" 

f Experiment.— TTo prepare hydrochloric acid gas, put several ounces of 
common salt and about twice as much sulphuric acid into a flask, and warm. 
The gas comes off in abundance and may be collected in a dry bottle (like 
chlorine, Fig. 12), or over mercury. The solution of the gas (the ordinary 
form) is obtained by passing the gas through a series of Wolff bottles contain- 
ing cold water and arranged as shown in Fig. 13. 



32 ESSENTIALS OF CHEMISTRY. 

Physical Properties. — Colorless, irritating gases; sharp, sour taste; 
very soluble, water dissolving several hundred times its own volume, 
forming agues known by the simple name of the acid itself, thus : The 
officinal "hydrochloric acid" is a solution of the hydrochloric acid 
gas in water. 

Chemical Properties, — Strong acids ; true acids even without 
water. 

Uses. — HF attacks silicon energetically, hence is used to etch glass ; 
very poisonous, and burns made by it heal with difficulty. 

HCl is very useful in the arts. Agua regia, or nitro-muriatic acid, 
is a mixture of nitric and hydrochloric acids. It is the only solvent 
of gold and platinum. The metals are attacked by the nascent 
chlorine evolved by the oxidation of the H of the HCl by the O of the 
HN0 3 . In medicine HCl is often prescribed as a tonic. 

HBr, like all bromides, is a sedative. HI, like all iodides, is an 
alternative. 

Tests. — Fluoride + H 2 S0 4 — etches glass. * 

Chloride + AgN0 3 — white precipitate, soluble in ammonia. 

Bromide + AgN0 3 — yellowish-white precipitate, slightly soluble in 
ammonia. 

Iodide + AgN0 3 — yellow precipitate, insoluble in ammonia. 

If to a bromide or iodide some chlorine-water and starch paste be 
added, the bromine and iodine will be liberated, the bromine striking 
a brown and the latter a blue color with the starch. 

Oxacids are formed by oxides of non-metals combining with water. 
The elements of the chlorine group, being very negative, have but 
little affinity for oxygen. Iodine has most, bromine less, chlorine still 
less, and fluorine will not unite with oxygen at all. 

Chlorine, bromine, and iodine each forms a series of oxides per- 
fectly analogous, so we will notice only those of one — chlorine. 

The several oxides are distinguished by prefixes derived from the 



* Experiment. — On a plate of glass coated with wax or copper-plate var- 
nish (six parts of mastic, one of asphalt, and one of wax dissolved in turpen- 
tine) draw a design with a pointed instrument. Invert over a lead dish and 
warm gently. Hydrofluoric acid gas is evolved and attacks the glass wherever 
the wax has been scratched off. Upon removing the wax the design is found 
permanently etched on the glass. 



PART I. — INORGANIC CHEMISTRY. 33 

Greek numerals indicating the number of oxygen atoms in the for- 
mula, thus : — 

C1 2 — Chlorine Monoxide. 

C1 2 2 (?) — Chlorine Dioxide. 
C1 2 3 — Chlorine Trioxide. 
C1 2 4 — Chlorine Tetroxide. 
C1 2 5 — Chlorine Pentoxide. 
C1 2 7 — Chlorine Heptoxide. 

These oxides combining with water form the corresponding acids, 
thus : — 

C1 2 -|- H 2 = 2HCIO — Hydrogen Hypochlorite — Hypochlorous acid. 
C1 2 3 + H 2 = 2HC10 2 — Hydrogen Chloride — Chlorous acid. 
C1 2 5 + H 2 = 2HCIO3— Hydrogen Chlorate— Chloric acid. 
Cl 2 O y -f- H 2 — 2HC10 4 — Hydrogen Perchlorate — Perchloric acid. 

Note. — The names of oxacids are derived from the negative element other 
than oxygen, and to this certain affixes and prefixes are added to indicate the 
degree of oxidation. The one containing more oxygen has the affix "-ic," less 
oxygen, " -ons" If there is in the same series another acid with more oxygen 
tha?i the " -ic," it is given the prefix "per-;" if less than the " -ous? 1 the pre- 
fix "hypo-" {tinder). Acids ending in " ~ic" form salts ending in " -ate;" 
those ending in "-ous" form salts ending in" -tie" The foregoing chlorine 
acids illustrate this. 

All these oxides, as well as their corresponding acids, are easily 
decomposed, sometimes with explosion ; hence much used as oxidiz- 
ing agents* and as explosive mixtures.! The most important of these 
salts is potassium chlorate, used in medicine and in the laboratory 
for the sake of its oxygen. 

* Experiment. — Their oxidizing action on combustibles may be shown by : 
(a) Mix together a drachm each of powdered potassium chlorate and sugar ; 
place on a brick and touch off with a glass rod dipped in sulphuric acid. A 
/igorous combustion occurs. (6) Drop some crystals of potassium chlorate 
ink a conical glass of water ; add several bits of phosphorus ; then by means 
of a pipette introduce sulphuric acid at the bottom of the glass. The phos- 
phorus takes fire and burns at the expense of the oxygen of the potassium 
chlorate. 

f Experiment. — Mix on a sheet of paper a scruple of powdered potassium 
chlorate and five grains of some combustible powder, as sulphur, antimony 
sulphide, or tannin. Wrap it up in the paper, place upon an anvil, and strike 
with a hammer. It explodes violently. 



34 



ESSENTIALS OF CHEMISTRY. 



III. Sulphur Group. 

Oxygen (already described), .0 16 

Sulphur, S 32 

Selenium, Se . 79.4 

Tellurium, Te 128 

The elements comprising this group are solid at ordinary tempera- 
tures ; bivalent and sexivalent ; possess electro-negative affinities 

Fig. 14. 




which, as in other groups, decrease as the atomic weights increase ; 
form hydracids as well as oxacids. 

The analogy between their compounds is shown in the following 
table :— 



Hydro-ic 
Acid. 

H 2 S 



H 2 Te 



Dioxide. 

. so 2 . 

. Se0 2 
. Te0 9 . 



Trioxide. 

.so, . 



Hypo-ous 
Acid. 

. H 2 S0 2 , 



-ous Acid. 

. H 2 S0 3 



. Se0 3 H 2 Se0 3 

. TeO q H 9 TeO, 



-ic Acid. 

. H 2 S0 4 . 
. H 2 SeO,. 
. H 2 Te0 4 . 



Selenium and Tellurium are of no medical interest, and will not be 
further noticed. 



PART I. — INORGANIC CHEMISTRY. 35 

SULPHUR occurs free, especially in the neighborhood of volcanoes ; 
occurs combined as sulphides and sulphates in many valuable ores, 
and in small quantity in the animal and vegetable kingdoms. 

Preparation. — The native sulphur freed from stones is refined by 
distillation, as shown in Fig. 14. The crude sulphur is melted in the 
tank by the hot draft from the fire below, and then runs down through 
a pipe into the retort, where it is vaporized. This vapor, entering a 
large brick chamber, is condensed in fine, feathery crystals, called 
flowers of sulphur or sublimed sulphur. If the chamber be hot, it 
condenses into a liquid, which is drawn off and moulded into rolls, 
called roll brimstone. Sublimed sulphur is apt to contain more or less 
acid, and is washed {sulphur lotuni). Boiled with lime and precipi- 
tated with HC1, it forms sulphur pre cipitatum, U. S. P. This mixed 
with water is milk of sulphur {lac sulphuris, U. S. P.). 

Physical Properties. — A brittle yellow solid ; insoluble in water, 
hence, tasteless, etc. 

Chemical Properties. — Inflammable, hence called "brimstone" 
(burn-stone). Combines with metals,* forming sulphides. f Sulphur 
forms compounds remarkably analogous to those of oxygen, e.g. .*— 

H 2 .... KHO .... C0 2 ... . H 2 C0 3 .... HCNO. 
H 2 S . . . . KHS .... CS 2 ... . H 2 CS 3 .... HCNS. 

Uses. — In the arts, to make gunpowder, matches, etc. ; in medicine, 
as a laxative, parasiticide, and alterative. We have only theoretical 
explanations of the method of its absorption ; but that it is absorbed 
is certain, for persons taking it excrete enough to blacken silver car- 
ried on the person. 

Hydrogen Sulphide — H 2 S — Hydro sulphuric Acid or Sulphureted 
Hydrogen — occurs in sewer gas and other effluvia from decomposing 
organic sulphurized matters, and in the water of sulphur springs. 

Prepared in laboratory by decomposing a sulphide, thus : — 

FeS + H 2 S0 4 = FeS0 4 + H 2 S. 

* Experiment. — In a small glass flask, a little sulphur is heated to boiling. 
If now a bundle of fine copper wire or a piece of sodium, in a combustion 
spoon, be previously heated and then lowered into the vapor, it burns brilliantly. 

f Experiment. — Mix in a dish equal parts of iron filings and flowers of 
sulphur : moisten with water and set aside. Within a half hour it gets hot, 
vaporizes the water, and isconverted into a black mass of FeS. 



36 ESSENTIALS OF CHEMISTRY. 

Physical Properties. — Colorless gas, having the odor of rotten eggs 

or intestinal flatus ; slightly soluble in water. 

Chemical Properties. — Very feeble acid ; burns with pale blue 

flame : — 

H 2 S + 3 - S0 2 + H 2 * 

Forms characteristic precipitates with most metallic salts, hence a 
valuable test reagent.f 

Tests. — The presence of H 2 S even in minute quantities may be 
detected by its odor, and by its blackening paper moistened with a 
solution of lead acetate. 

Fig. 15. 




Preparation of H 2 S. 

Physiological. — When inhaled H 2 S is an active poison, combining 
with the hemoglobulin and destroying its oxygen-carrying power. 
Even when highly diluted, as in the atmosphere of city dwellings, 

* Experiment. — Burn the gas from a jet : (a) Hold near the flame a glass 
rod dipped in ammonia ; white crystals of ammonium sulphite are formed. 
(6) Hold a cold, dry bell glass over the flame ; it is bedewed with water. 

f Experiment. — To show the action of H 2 S on metallic salts, connect 
several wash bottles with the generator A, as shown in Fig. 16. A dilute solu- 
tion of lead acetate is put in B, of tartar emetic (antimony) in C, of arsenic in D, 
of zinc sulphate in E. The gas in passing precipitates lead sulphide (black) 
in B, antimonious sulphide (orange) in C, arsenious sulphide (yellow) in D, 
zinc sulphide (white) in E. 



PART I. — INORGANIC CHEMISTRY. 



37 



clumsily " fitted with the modern conveniences," it produces a low 
febrile condition. When concentrated, or even moderately diluted 
(one per cent, and over), the gas proves rapidly fatal. 

Treatment. — Fresh air, artificial respiration, and stimulation. 

Carbon Disulphide — CS 2 . — Obtained by bringing S into contact 
with heated charcoal. A colorless, volatile liquid of a fetid odor, 
unless it is very pure. A valuable solvent for S, P, india-rubber, etc. 



Fig. 16. 




Sulphur Oxides and Acids. 

Dioxide — S0 2 -f- H 2 = H 2 S0 3 — Sulphurous acid. 
Trioxide— S0 3 -f- H 2 = H 2 S0 4 — Sulphuric acid. 

Sulphur Dioxide, S0 2 , occurs whenever sulphur or any of its 
compounds are burned in air or oxygen. 

Prepared in laboratory by decomposing sulphuric acid by copper 
or charcoal, thus : — 

2H 2 S0 4 + Cu = CuS0 4 + 2H 2 + S0 2 . 
2H 2 S0 4 + C =2S0 2 -f C0 2 +2H 2 0. 

Physical Properties. — A colorless gas, with a suffocating odor 



38 ESSENTIALS OF CHEMISTRY. 

(of burning matches) ; dissolves in water to form sulphurous acid 
(H0SO3). 

Chemical Properties. — Neither burns nor supports combustion ; a 
strong deoxidizer ; by removing O from coloring matters and infecting 
germs it bleaches * and disinfects. 

Uses. — Sulphur dioxide, sulphurous acid, and the sulphites possess 
the property of destroying microorganisms and arresting fermenta- 
tions. A sulphite digested with sulphur forms a hyposulphite, thus : — 

Na 2 S0 3 + S = Na 2 S 2 3 - 

Sodium hyposulphite has the same uses as the sulphites, and is also 
a valuable solvent of the silver salts in photography. 

Sulphur Trioxide, S0 3 . — Made by oxidizing S0 2 in the manu- 
facture of sulphuric acid. This is done upon a large scale by passing 
S0 2 from burning sulphur into a chamber kept rilled with vapor of 
nitric acid, steam and air. f The nitric acid gives up a part of its 
oxygen to oxidize a portion of the S0 2 to S0 3 . 

2HNO3 + 3S0 2 = 3SO3 + H 2 + N 2 2 . 

The S0 3 then combines with the water thus produced (S0 3 + H 2 
= H 2 S0 4 ), and more water is supplied by a jet of steam thrown con- 
stantly into the chamber. 

The N0O0 has the power of taking up oxygen from the air and be- 
coming N0O4, 

N 2 2 + 2 -= N 2 0„ 

which in turn parts with this oxygen to oxidize a new quantity of S0 2 . 
N 2 4 + 2S0 2 == N 2 2 + 2SO3. 
Thus the process is kept up as long as the S0 2 , air, steam, and N 2 2 



* Experiment. — Some sulphur is ignited beneath a tripod on which fresh 
flowers are placed, and the whole covered by a bell-glass. The flowers are 
bleached. The color may be restored by washing with some dilute alkali or 
acid that will combine with or displace the S0 2 , or with very dilute nitric acid, 
which will restore the oxygen removed by the S0 2 . 

-j- The manufacture of sulphuric acid may be illustrated on the lecture table 
by the apparatus shown in Fig. 17. The lead chamber is represented by a 
large flask. Into this are led (a) N 2 2 from the flask on the right ; {b) S0 2 
from a mixture of sulphur and manganese dioxide in the flask in the rear; 
(c) steam from the other flask, and (d) air or oxygen through the open tubes. 



PART I. — INORGANIC CHEMISTRY. 



39 



are supplied. The acid condenses with the water upon the floor of 
the chamber, and is drawn off, concentrated, and sold as 

Sulphuric Acid— H 2 S0 4 — " Oil of Vitriol" 

Physical Properties. — A dense, colorless, oily-looking liquid, with- 
out odor. 

Che?nical Properties. — Strong acid ; very avid of water, not only 
dissolving in it, but combining with it, the act evolving considerable 
heat ; chars organic matters by abstracting H and O to form water.* 

Fig. 17. 




Uses. — So important in the arts that the commercial prosperity of a 
country may be measured by the amount of H 2 S0 4 consumed. Prop- 
erly diluted, it is a refrigerant tonic, but concentrated it is a severe 
caustic. 

Tests, — (1) The concentrated acid, if placed on a piece of paper or 



* Experiment. — Pour strong sulphuric acid on an equal quantity of sugar 
or strong syrup; the sugar is dehydrated and a mass of carbon left. 



4o 



ESSENTIALS OF CHEMISTRY. 



other organic material, will char it. If dilute, it will char the paper 
only after being warmed and concentrated by the evaporation of its 
water. (2) Sulphuric acid, or any other sulphate, will form with a 
solution of a barium salt a white precipitate (BaS0 4 ) insoluble in nitric 
or hydrochloric acid. 



IV. Nitrogen Group. 

Nitrogen, N 14 

Phosphorus, P 31 

Arsenic, As 75 

Antimony (Stibium), Sb 122 

Bismuth, Bi ^ . 210 

Trivalent and Quinquivalent. — This group, as shown below, forms 
a graded series from nitrogen and the negative to bismuth at the 
positive end : — 

N P As Sb Bi 

14 31 75 122 210 

Sp. gr. 1.83. Sp. gr. 5.67. Sp. gr. 6.7. Sp. gr. 9.8. 

Gas, with full A soft solid. Solid. Hard solid. Very hard solid, 

negative ten- Non-volatil- 

dencies. Easily volatiliz- Volatilizable. Difficultly vola- izable. 

able. tilizable. Full metallic lus- 

Destitute of me- Some metallic Great metallic tre. 

tallic lustre. lustre. lustre. Full positive ten- 
Negative ten- Both negative More positive dencies. 
dencies. and positive tendencies, 
tendencies. 

The following will exhibit the relations of some of the most import- 
ant compounds : — 

Hydrides. Chlorides. Oxides. Sulphides. 

-ous. -ic. -ous. -ic. 'ous. -ic. 

NH 3 NCI3, . . NA, N 2 5 . . . . 

PH S PCI3, PC1 5 p 2 o 3 , P 2 5 P 2 S 3 , P 2 S 5 

AsH 3 AsCl 3 , AsCl 5 As 2 3 , As 2 O s As 2 S 3 , As 2 S 5 

SbH 3 SbCl 3 , SbCl 5 Sb 2 3 , Sb 2 5 Sb 2 S 3 , Sb 2 S 5 

. . BiC] 3 , . . Bi 2 3 , Bi 2 5 . . . . 

NITROGEN occurs uncombined in the atmosphere ; combined in 
some mineral and in all vegetable and animal bodies, especially in the 
more highly organized tissues. 

Prepared most easily by burning phosphorus in a confined space 



PART I. — INORGANIC CHEMISTRY. 



41 



until the oxygen is removed from the air.* Prepared in this way it 
contains small quantities of other gases found in air. To prepare 
it pure, heat ammonium nitrite (NH 4 N0 2 = 2H 2 + N 2 ). 

Physical Properties. — A colorless, tasteless, odorless gas, a little 
lighter than air. 

Chemical Properties. — Little tendency to combine with other ele- 
ments, and its compounds, once formed, are very prone to decom- 



Fig. 18 




pose, either with violent decomposition f or gradual putrefaction ; 
neither combustible nor a supporter of combustion ; negatively poison- 
ous. 
The Atmosphere. — Air, J considered by the ancients one of the 



* Experiment. — A flat piece of cork floating on water supports a capsule 
containing a bit of phosphorus carefully dried. This is ignited and immedi- 
ately covered with a bell jar. The jar is filled with a dense white cloud from 
the combustion, which ceases only when the oxygen is all consumed. At first 
the air expands and some may be forced out. Upon cooling the water rises to 
take the place of the oxygen, and the white fumes gradually dissolve in the 
water, and the nitrogen is left clear and comparatively pure. 

f Experiment. — To tincture of iodine add excess of ammonia water. Filter 
to separate the precipitated iodide of nitrogen. Put portions of this on separate 
bits of paper and set aside. When dry they explode on the slightest touch. 

% Proofs that air is a mixture: (1) Its constituents are not in atomic pro- 
portions; (2) air can be made by mechanically mixing the gases; (3) solvents 
may remove one gas without affecting the others, each dissolving according to 
its own solubility. 



42 ESSENTIALS OF CHEMISTRY. 

four elements, is neither an element nor a compound. It is a mixture 
mainly of nitrogen and oxygen, the function of the former being to dilute 
the latter. Miller gives the average composition of air as follows : — 

Volumes. 

Nitrogen, 77-95 

Oxygen, 20.61 

Carbon dioxide, 04 

Aqueous vapor, 1.40 

Also traces of nitric acid, ammonia, sodium chloride, ozone, dust, 
bacteria, germs, etc. In the neighborhood of large cities various other 
substances are poured into the air from manufactories. Yet, owing to 
the rapid diffusion of gases, the composition of the air is almost the 
same everywhere. 

Watery Vapor. — The higher the temperature the more water air 
will hold. A warm, dry air, when cooled, will appear damp, and the 
temperature at which it begins to deposit its water is its dew-point. A 
cold, damp air, when heated, becomes capable of holding more water, 
and appears dry ; hence the necessity of supplying water to the heated 
air of our rooms in winter, especially in cases of bronchitis or catarrhal 
croup. Even in health a very dry air irritates the air-passages, pro- 
duces dryness of the skin and malaise ; while a very moist atmos- 
phere retards evaporation from the skin and lungs, raises the body 
temperature, and becomes oppressive. 

Suspended matters in air are of a great variety of substances. The 
irritation of dust incident to certain trades may cause chronic bron- 
chitis, emphysema, and phthisis. * Germs floating in the air are believed 
to be the cause of many contagious, infectious, and malarial diseases. 
The best disinfectants * are (a) free ventilation and consequent dilu- 
tion ; (J?) chlorine, bromine, iodine, and sulphur dioxide. 

Nitrogen Hydride — Ammonia, NH 3 . — Occurs in the effluvia from 
decomposing nitrogenized organic bodies ; for nitrogen and hydrogen 
unite only in the nascent state. (See page 26.) First obtained by 
distilling camel's dung, near the temple of Jupiter Ammon in Libya ; 
hence called " ammonia." Obtained by heating clippings of hides, 



* Disinfectants destroy the power to infect, whether it be due to germs or 
other agent. Ger??zicides destroy germs. Antiseptics prevent putrefaction. 
Antizymotics prevent fermentation. Deodorizers destroy offensive odors. 



PART I. — INORGANIC CHEMISTRY. 



43 



hoofs and horns,* especially of deer, in closed retorts (destructive 
distillation), it was called spirit of hartshorn. Coal contains about two 
per cent, of nitrogen, which in the manufacture of coal gas comes 
off as ammonia. In washing the coal gas the ammonia dissolves in 
the water. This aqua is its commercial source. 

Prepared in laboratory by driving the ammonia off from the aqua by 
means of heat. 

Fig. 19. Fig. 20. 





Physical Properties. — Transparent, colorless gas, of an irritating 
odor ; condenses under a pressure of 6 l /2 atmospheres into a colorless 
liquid ;f very soluble in water, which dissolves from 500 to 1000 
times its own volume. % Administered by inhalation as a stimulant 

* Experiment. — Mix calcium, potassium, or sodium hydrate with some 
nitrogenous substance, as albumin or clippings of horn, hoofs, flannel or lean 
meat. Heat in a test-tube. Ammonia gas is evolved, recognized by its odor, 
alkalinity, or by white fumes forming when a glass rod moistened with HC1 is 
thrust into the tube. 

f Experiment. — Make ammonium silver chloride by passing ammonia gas 
over silver chloride. Enclose this in a bent tube (Fig. 20). The end contain- 
ing the compound is heated in a water bath, while the other is cooled in an ice 
mixture. Ammonia gas is driven off from the compound, and condenses into 
a colorless liquid in the cold end of the tube. 

% Experiment. — The absorption of ammonia gas by water may be illus- 
trated by filling a large bottle with the gas by upward displacement and closing 
the mouth with a rubber cork through which passes a glass tube sealed at the 
outer end. If this sealed end be plunged under water and then broken off, the 
water rushes in, forming a fountain (Fig. 19). If the water be colored with 
red litmus solution it will become blue as it enters the bottle, showing the 
alkalinity of the solution. 



44 



ESSENTIALS OF CHEMISTRY. 



in fainting fits, etc., but care must be taken, for its too liberal use 
may cause spasm of the glottis or induce a fatal bronchitis. 

Tests. — (i) Smell; (2) white fumes with HC1; (3) turns moistened 
red litmus paper blue. 
Nitrogen Oxides. 

Monoxide— N 2 + H 2 — 2HNO = Hyponitrous acid. 
Dioxide — N 2 2 . No corresponding acid. 
Trioxide— N 2 Q 3 + H 2 = 2HN0 2 = Nitrous acid. 



Tetroxide- 
Pentoxide- 



No corresponding acid. 



-N 2 5 + H 2 : 



Fig. 2 




Making N 2 0. 



Nitrogen Monoxide— N 2 {Nitrous Oxide— Laughing Gas). — 
Prepared 'by heating ammonium nitrate, as shown in Fig. 21. 

NH 4 N0 3 = N 2 + 2H 2 0. 

Physical Properties. — Colorless, odorless gas, of sweetish taste. 
Dentists keep it liquefied under pressure in iron cylinders. 

Chemical Properties. — By the ease with which it gives up its O it is 
a supporter of combustion and life, next to O itself. 

Medical. — Inhaled, diluted with air, it produces exhilaration of 
spirits, muscular activity, and then complete anaesthesia. Used in 
dental and other brief minor operations. 



PART I. — INORGANIC CHEMISTRY. 45 

Nitrogen Dioxide — N 2 2 (Nitric Oxide). — Prepared by action 
of nitric acid on copper : — * 

3 Cu + 8HNO3 = 3Cu(N0 3 ) 2 + 4 H 2 + N 2 2 . 

A colorless gas, which, when coming in contact with free O, forms red 
vapors of N 2 3 and N 2 4 ; hence a test for free O. 

Nitrogen Trioxide — N 2 3 (Nitrous Acid— HN0 2 ). — Nitrous acid 
is known only in its salts, the nitrites. These are produced in nature 
by the oxidation of nitrogenous organic matter in the presence of cer- 
tain forms of microscopic life. 

This nitrification occurs in waters polluted with organic matter, and 
normally in the soil, where the acid so formed combines with bases. 
Hence nitrites in water is evidence of previous contamination with 
nitrogenous matter. Further oxidation forms nitrates. 

Nitrogen Tetroxide — N 2 4 — occurs in company with N 2 3 in the 
brown fumes given off whenever nitric acid is decomposed, as in cer- 
tain laboratory and manufacturing processes. The effect of breathing 
air thus contaminated is to produce chronic inflammation of the respira- 
tory tract. If the vapor be more concentrated the effects are more 
acute and serious. At first there is only a cough, in two or three 
hours a difficulty of breathing, and in about twelve hours, death. The 
remedy is ventilation. 

Nitrogen Pentoxide — N 2 5 — is of no medical interest. 

Nitric Acid — HN0 3 (Aqua Fortis) — occurs in traces in the atmos- 
phere and as nitrates in the soil. (See Nitrites.) 

Prepared by distilling a nitrate with sulphuric acid. 

2KNO3 + H 2 S0 4 = K 2 S0 4 + 2HN0 3 .t 



* Experiment. — Copper turnings, clippings, or wires are placed in a flask, 
and nitric acid diluted with half its volume of water is poured in, and the flask 
set in cold water. Red fumes soon fill the flask, but when these have escaped 
the gas appears colorless, turning red, however, on reaching the air. The 
colorless gas is collected over water. 

I Experiment. — In the laboratory nitric acid may be prepared with the 
apparatus shown in Fig. 22. Equal parts of sodium nitrate and sulphuric acid 
are heated in the retort. The nitric acid produced is vaporized by the heat and 
recondensed in a receiver kept cool by a wet cloth, over which flows a stream 
of water from an elevated vessel. 



4 6 



ESSENTIALS OF CHEMISTRY. 



Physical Properties. — Heavy liquid, colorless, but if old and exposed 
to light it may be yellow or orange from presence of N 2 3 and N 2 4 . 
Like all other nitrates, it is soluble in water. 

Chemical Properties. — Energetic oxidizer ; * corrosive ; stains skin 
indelibly yellow. 

Medical Uses. — The strong acid is an escharotic,. coagulating the 
albumin of the tissues ; the dilute, a refrigerant tonic. 

Tests. — (i) Yellow stain. (2) Add H 2 S0 4 , and then a crystal of 
FeS0 4 dropped in will be colored brown if nitric acid or any nitrate be 
present. 

Fig. 22. 




Making HN0 3 . 

PHOSPHORUS (Light-bearer) occurs combined with O in the 
ancient unstratified rocks. These disintegrate and form soil, from 
which the P passes into the organisms of plants, and thence into the 
bodies of animals. First isolated by Brandt (1669) from urine; now 
obtained from bones. 

Physical Properties. — A soft, yellowish solid, resembling unbleached 



* Experiment. — Into a mixture of strong sulphuric and nitric acids pour 
from a beaker tied to a long stick some warm turpentine. The oxidation is so 
rapid that the turpentine is inflamed. 



PART I. — INORGANIC CHEMISTRY. 47 

wax.* Insoluble in water, but soluble in carbon disulphide, ether, 
chloroform, oils, etc. 

Chemical Properties. — Very inflammable,! so kept under water ; 
exposed to the air, it undergoes a slow combustion, emits the odor of 
ozone, and is luminous in the dark. 

Physiological. — Liable to inflame from careless handling, and burns 
by it are difficult to heal. In medicinal doses, a nerve tonic and 
aphrodisiac ; in larger quantities a virulent poison and gastro-irritant. 
Sometimes given with homicidal intent, but more frequently taken 
accidentally as rat poison, tips of matches, etc. Workmen in match 
factories suffer from irritation of stomach and bowels, caries of teeth, 
necrosis of bones, especially of lower jaw, and from fatty degenera- 
tion of various organs. This may be prevented by using the red 
allotropic variety, which is harmless. 

No good antidote. Evacuate the stomach ; give copper sulphate % 
as emetic and antidote; give old turpentine, the ozone of which 
oxidizes the P. Avoid fats, for they dissolve it. 

Tests. — (i) Shines in the dark; (2) emits garlicky odor. 

Phosphorus Hydride. — PH 3 {Phosphoretted Hydrogen — Phos- 
phine) — occurs mixed with other hydrides of P in the gases arising 
from decomposing animal or vegetable matters, especially under 
water; hence seen as the ignis fatuus, or "Will-o'-the-wisp," over 
marshes and graveyards. 

Prepared 'by boiling phosphorus in a solution of caustic potash. § 
* 

* When heated to 500 F. in an atmosphere incapable of acting upon it, phos- 
phorus is converted into a reddish- brown powder, which, unlike ordinary phos- 
phorus, is not poisonous, not inflammable, and insoluble in the ordinary solvents. 

I Experiment. — Dissolve some phosphorus in carbon disulphide. Pour 
this on a sheet of filter paper hung on a retort stand. Soon the solvent evapo- 
rates and leaves the phosphorus in such a fine state of division that it inflames 
spontaneously. 

X Experiment". — Place a clean bit of phosphorus for a minute in a solution 
of copper sulphate. Remove, and note the coating of metallic copper. 

\ Experiment. — Into a retort, whose delivery tube dips under water in a 
dish, add liquor potassse and a few bits of phosphorus. Expel the air by pass- 
ing hydrogen or illuminating gas through the retort, or by adding a few drops 
of ether, the vapor of which does the same thing. On applying heat the 
hydrogen or illuminating gas or ether vapor first escapes, then come bubbles 
of PH 3 , each of which, as it bursts into the air, ignites spontaneously, forming 
beautiful rings of white smoke rotating on their circular axes. These may 
ascend to the ceiling if the air be still. 



48 



ESSENTIALS OF CHEMISTRY. 



Properties. — Colorless gas, of a garlicky odor ; inflames spontane- 
ously upon coming in contact with the air ; very poisonous. 

Phosphorus Oxides. These are analogous to the oxides of 
hydrogen, and form, on the addition of water, analogous acids. 

Phosphorus Pentoxide (P 2 5 ) is produced whenever P burns in 



Fig. 23. 




air* or O ; and forms three different phosphoric acids by combining 
with one, two or three molecules of water, thus : — 

PA + 3H 2 = H 6 P 2 8 



2H 3 P0 4 = Orthophosphoric acid. 

Pyrophosphoric acid. 

2HPO3 — Metaphosphoric acid. 

Orthophosphoric Acid.— Never found free, but is widely dis- 



P 2 5 + 2H 2 = H 4 P 2 7 
P 2 5 + H 2 =H 2 P 2 6 : 



* Experiment. — A little stand in the middle of a dinner-plate supports a 
capsule, into which is put a bit of phosphorus freed from adhering water. This 
is ignited and covered with a bell jar. This jar is rilled with clouds of P 2 5 , 
which, aggregating, fall into the plate like a miniature snow-storm. 



PART I. — INORGANIC CHEMISTRY. 49 

seminated in the three kingdoms of nature in its salts, the phos- 
phates. Being the phosphoric acid most used in medicine (the 
other two are poisonous), it is usually called simply " phosphoric 
acid." Transparent, odorless, colorless, syrupy liquid. Being tri- 
basic, it forms three classes of phosphates by displacement of one, 
two, or three atoms of the basic hydrogen, thus: — 

KH 2 P0 4 , K 2 HP0 4 , and K 3 P0 4 . 

In the diluted form (acidum phosphoricum dilutum) it is prescribed 
as a tonic, especially in dyspepsia. 

Tests. — Add a few drops«of the magnesian fluid (MgS0 4 , NH 4 C1, 
and NH4HO, each one part, water eight parts) ; a white precipitate 
indicates phosphoric acid or other phosphate. 

ARSENIC occurs mostly as sulphide, usually associated with other 
metals. The ore is roasted, and the resulting oxide heated with 
carbon (charcoal) gives the metal. This is a brittle, steel-gray, crys- 
talline solid, possessing a metallic lustre. Heated out of contact with 
air it sublimes ; in air it burns with a bluish-white flame, emitting the 
odor of garlic and white clouds of As 2 3 . It combines with many 
elements ; the metallic arsenides resemble alloys. Used in pyrotechny 
and in the manufacture of shot, pigments and fly-poison. All its 
compounds are poisonous. 

Arsenious Hydride — AsH 3 — Arseniuretted Hydrogen — Arsine — 
is of great practical interest to the toxicologist, as its formation con- 
stitutes one of the most delicate tests for arsenic. Forms whenever 
hydrogen is generated in presence of an arsenical compound. 

Arsenious Iodide — Asl 3 . — Prepared by fusing together atomic 
proportions of its constituent elements. It enters into Donovan s 
Solution, liq. arsenii et hydrargyri iodidi, U. S. P. 

Arsenious Sulphide — As 2 S 3 — occurs native as orpiment. Pre- 
pared by precipitating an arsenious ■ compound with H 2 S. Bright 
yellow powder, insoluble in water or acid solutions, but soluble in 
alkaline. Another sulphide is realgar, AsS 2 . Both are used as pig- 
ments — the orpiment as a yellow, the realgar as a red. 

Oxides and Acids. 

As 2 O s -f- 3H 2 == 2H 3 As0 3 , (ortho) Arsenious acid. 
As 2 5 + 3H 2 == 2H 3 As0 4 , (ortho) Arsenic acid. 



50 ESSENTIALS OF CHEMISTRY. 

Arsenious Oxide — As 2 3 . Arsenic, White Arsenic, Ratsbane, 
Arsenious Acid. — This is not only the most important compound of 
arsenic, but the most important of toxic agents, whether we consider 
the deadliness of its effects or the fatal frequency of its administration. 
When recently made it is in glassy lumps, which on exposure become 
crystalline and opaque. When sublimed it is deposited again in 
brilliant octahedral crystals. It is odorless, almost tasteless — slightly 
sweetish. When powdered arsenic is thrown upon water it does not 
all sink, notwithstanding its heaviness, but floats, showing a repulsion 
of the water. Very slightly soluble in water, even boiling water dis- 
solving less than two per cent. If the water be made acid or alkaline, 
it dissolves more readily. When arsenic dissolves in water it forms 
arsenious acid, H 3 As0 3 . 

There are two officinal solutions, each containing one per cent, of 
arsenic : (i) Liq. acidi arseniosi, in which the water is acidulated with 
HC1 ; (2) Fowlers Solution, liq. potassii arsenitis, in which the water 
is made alkaline by K 2 C0 3 . 

Arsenic Oxide. — Arsenic pentoxide is made when arsenious oxide 
(As 2 3 ) is treated with an oxidizing agent, as nitric acid. It is quite 
soluble in water, with which it forms a series of arsenic acids (ortho-, 
pyro- and meta-) analogous to the phosphoric acids. 

Toxicology of Arsenic. — The deadly effect of arsenical compounds 
has been known from remote antiquity, and they have probably been 
more used for homicidal purposes than all other toxic agents com- 
bined. Although chemistry has made its detection easy and certain, 
arsenic is so cheap, so readily administered to the unsuspecting 
victim, and so deadly, that it is still a favorite with the murderer. 
Owing to the extensive use of arsenical compounds as insect-powders 
(Paris green, etc.), and as pigmentsTor wall-paper, toys, confectionery, 
etc., cases of accidental poisoning are quite common. 

Few physicians have the training and facilities to undertake an 
extended analysis, but they should all know the simpler tests, so as to 
promptly recognize the nature of the poison and combat it intelli- 
gently and successfully. Besides, the physician, being early in the 
case, can by wise precautions prevent breaks in the chain of evi- 
dence ; protecting the prisoner if innocent, and closing loop-holes of 
escape if guilty. If foul play is suspected, he should commit all his 
observations to writing, for notes to be admitted as evidence must be 
the original ones taken at the time. Having collected the urine, 



PART I. — INORGANIC CHEMISTRY. 5 1 

faeces, vomit, and the suspected vehicle of the poison, and having 
tested some or all of them to verify his suspicion, he should place 
them under seal or lock and key. He should carefully reserve his 
opinion, lest he do injustice to the innocent or warn the guilty. In 
case of death, the coroner should be notified and an autopsy held, in 
presence of the chemist if possible. The stomach and entire intestinal 
canal, ligated at both ends, half of the liver, the whole brain, spleen, 
one kidney, and any urine remaining in the bladder should be saved. 
These, if possible, should be preserved in separate jars, to which a 
little pure chloroform may be added to prevent decomposition. These 
jars must be new and clean, closed with new corks or glass — not zinc 
caps. They are then to be labeled, and also sealed and stamped, 
so they cannot be opened without detection, and as soon as possible 
turned over to the chemist or prosecuting officer. 

The symptoms of arsenical poisoning are those common to all intense 
irritants, viz., nausea, vomiting, burning pain in the epigastrium, 
purging, cramps, thirst, fever, rapid pulse, etc., ending in collapse. 
Smallest fatal dose is two grains, and death usually occurs in twenty- 
four hours. 

Treatment. — Remove any unabsorbed poison from the stomach by 
emetics or stomach-pump. The best antidote* is freshly precipitated 
ferric hydrate, made by adding aqua ammoniae to a solution of a 
ferric salt. " Dialysed iron," being a solution of ferric hydrate, may 
be used. It should be given at frequent intervals and in tablespoonful 
doses. 

Tests for Arsenic. — In the solid state : i. Heated on a knife- 
blade over a lamp, it volatilizes with a white smoke, and leaves no 
residue. 

2. Heated in a test-tube it sublimes, and is recondensed in the cooler 
portion of the tube (Fig. 24) as octahedral crystals (Fig. 25). 

3. Heated in a small tube with powdered charcoal, the arsenic is 
reduced as it sublimes, and recondenses on the cooler portion of the 
tube in the metallic state. 

In the liquid state : 1. Through the solution, acidulated or rendered 
neutral, pass H 2 S ; a yellow precipitate (As 2 S 3 ) falls. 

*An antidote is something harmless and capable of rendering the poison 
harmless. Since poisons are inert when insoluble, antidotes are usually such 
substances as are capable of combining with the poison to form an insoluble 
and therefore inert compound. 



52 



ESSENTIALS OF CHEMISTRY. 



2. To an aqueous solution add a few drops of nitrate of silver, and 
then cautiously add ammonia, drop by drop, till a yellow precipitate, 
silver arsenite (Ag 3 As0 3 ) is obtained, showing the presence of arsenic. 

3. Repeat the preceding, adding copper sulphate instead of silver 
nitrate, and the presence of arsenic is indicated by a green precipitate 
of copper arsenite (Scheele's green or Paris green). 

The last two tests may be performed with greater ease and delicacy 
if the silver nitrate and copper sulphate each be previously treated 
with ammonia until the precipitate first formed is barely dissolved, 
forming solutions of ammonio-nitrate of silver and ammonio-sulfthate 
of copper, which are filtered and set aside as test reagents. 



Fig. 24. 



Fig. 25. 





The Plating (Reinsch's) Test. — Place a thin piece of pure copper 
in the solution acidulated with HC1, and boil. If arsenic be present, 
it will be deposited as a metallic film on the copper. If the solution 
be then poured off, and the piece of copper, carefully dried, be heated 
in a dry test-tube, the film will sublime and condense on the sides of 
the tube, and the preceding tests may be applied. 

The Hydrogen (Marsh's) Test depends on the fact that AsH 3 is 
always formed whenever hydrogen is generated in the presence of any 
arsenical compound. Generate hydrogen (Fig. 26) in the usual way 
(Zn + H 2 S0 4 ), and if the chemicals are pure (free from arsenic), the 
gas burns with a pale yellowish flame, without odor, and does not stain 
a porcelain dish held in the flame. Then pour into the generator 
some of the suspected solution. If arsenic be present, there is an 
odor of garlic ; the flame becomes bluish-white, and a cold porcelain 



PART I. — INORGANIC CHEMISTRY. 



53 



dish held in the jet (Fig. 28) so chills the flame that only the H burns, 
and the As is deposited on the porcelain as a brilliant metallic film. 



Fig. 26. 





Fig. 28. 



If the delivery tube be heated (Fig. 27), the 
passing AsH 3 is decomposed, and metallic ar- 
senic deposits farther out in the tube in a film of 
the same character as that on the porcelain. 

This may be distinguished from the film 
formed by antimony under similar circumstan- 
ces by (1) its greater metallic lustre, and (2) by 
its dissolving on the addition of chlorinated 
soda (Labarraque's solution); (3) 
moisten the spot with nitric acid ; 
evaporate the acid ; a white stain is 
left, which is colored a red by AgN0 3 and yellow by H 2 S. 
The flame should now be extinguished and the delivery-tube 
made to dip into a solution of AgN0 3 . This will be black- 
ened, and, if overlaid with aqua ammoniae, a yellow pre- 
cipitate will appear at the junction of the two fluids. 

ANTIMONY (stibium) occurs native, but usually as a sulphide. 
Prepared by roasting the sulphide, and heating the oxide thus ob- 
tained with charcoal. 

Properties. — A bluish-white, brittle, crystalline solid, with a brilliant 
metallic lustre. Resembles metals and forms alloys. In chemical 



54 ESSENTIALS OF CHEMISTRY. 

properties it plays the role of positive and negative radical with 
equal facility. 

Used in alloys, as type metal, Babbitt's metal, Britannia, etc., to 
which it gives hardness and causes them to expand and fill the moulds 
on solidifying. The metal is not used in medicine, most of the com- 
pounds being obtained from the sulphide. 

Antimonious Hydride — SbH 3 {Antimoniuretted Hydrogen — Sti- 
bine), corresponding to AsH 2 . — This gas is formed wherever hydrogen 
is generated (nascent) in presence of a reducible antimony compound. 

Antimonious Chloride — SbCl 3 . — At ordinary temperatures a yel- 
low semi- solid ; hence called butter of antimony. On addition of 
considerable water it decomposes, precipitating a white powder, the 
oxychloride (SbO.Cl),* formerly called powder of algaroth. 

Oxides and Acids of Antimony. 

Sb 2 3 + H 2 = 2HSb0 2 — (meta) Antimonious acid. 
Sb 2 5 + H 2 = 2HSb0 3 — (meta) Antimonic acid. 

Antimonious Oxide — Sb 2 3 .— Prepared by treating the oxychloride 
with sodium carbonate to remove the chlorine. A whitish, insoluble, 
volatilizable powder. 

Antimony and Potassium Tartrate-— (SbO)KTf ( Tartar Emetic). 
Prepared by treating Sb 2 3 with the bitartrate of potassium, thus : — 

2KHT + Sb 2 3 = 2(Sb0)KT + H 2 0. 

Sweetish, metallic taste ; soluble in water and slightly so in alcohol. 
Dissolved in Sherry wine it forms vinum antimonii, U. S. P. It enters 
also into unguentum antimo7iii and syrupus scillce compositus, U. S. P. 

Antimonious Sulphide — Sb 2 S 3 , the principal ore of antimony ; 
occurs native in black, lustrous masses. It may be precipitated from 
any antimonial solution by H 2 S as an orange powder, jwhich is black 
when thoroughly dried. 

Poisoning by antimony occurs oftenest with tartar emetic, for that 
salt is used more than all the other compounds of antimony. The 

* SbO and BiO, called respectively antimony I and bismuthyl, are univalent 
radicals, because two valences of the trivalent element being satisfied by the 
bivalent O, only one free valence is left. 

f (T) is used to represent the tartaric acidulous radical (C 4 H 4 6 ). 



PART I. — INORGANIC CHEMISTRY. 55 

symptoms are those referable to gastro-enteric irritation. Fortunately 
the salts of antimony are emetic, and cause spontaneous evacuation 
of the stomach. Encourage this, and give tannic acid or ferric 
hydrate, which will form an insoluble compound. 

The presence of antimony may be detected by (i) orange precipi- 
tate with H 2 S ; (2) by Marsh's test (see page 52). 

BISMUTH occurs native and as sulphide. Prepared by roasting 
the sulphide in air, and reducing the resulting oxide with charcoal. 

Properties. — A brittle, white metal, with a bronze tint ; volatilizes 
at a white heat. Forms compounds closely analogous to those of Sb, 
but is more positive, and plays the negative role with less facility. 

Used in alloys; e.g., pewter and stereotyping metal; the latter 
melts in boiling water. 

Bismuth Nitrate — Bi3N0 3 . — Formed by treating bismuth with 
nitric acid. Dissolves in a little water, but if much water be added 
it decomposes, with precipitation of — 

Bismuth Subnitrate — BiON0 3 {Bismuth Oxy nitrate) — a white, 
tasteless powder, much used in medicine and as a cosmetic (pearl 
white). 

Bismuth Subcarbonate — (BiO) 2 C0 3 . — Similar to the preceding in 
constitution, properties, and uses. 

Bismuth and Ammonium Citrate. — Obtained in pearly scales by 
dissolving the citrate in dilute ammonia-water, evaporating to a 
syrupy consistence and spreading on glass to dry. Being very 
soluble it is the preparation used in making the popular elixirs of 
bismuth. 

Physiological. — The bismuth salts are tonic, sedative, mildly astrin- 
gent and antifermentative. Used to allay gastro-intestinal irritation. 
Occasionally the irritation is increased from presence of arsenic 
which unscrupulous manufacturers often fail to remove as the Phar- 
macopoeia directs. When preparations of bismuth are taken, the 
stools are blackened by the sulphide formed with the H 2 S in the 
intestines. In severe cases of diarrhoea, with acid fermentation, this 
blackening does not occur, and its reappearance is a sign of improve- 
ment. 

Tests. — (1) H 2 S or NH 4 HS gives brownish-black precipitate; (2) the 
concentrated solution poured into water forms a white precipitate. 



56 ESSENTIALS OF CHEMISTRY. 

V. Carbon Group. 

Carbon (carbo, a coal) , C, 12 

Silicon (silex, a flint), Si, ...... 28 

Tin (Stannum), Sn, 118 

Lead (Plumbum), Pb, 207 

Each element is bivalent and quadrivalent. The dioxide of each 
forms with water a dibasic acid : — 

C0 2 + H 2 = H 2 C0 3 , Carbonic acid. 
Si0 2 -f- H 2 = H 2 Si0 3 , Silicic acid. 
Sn0 2 -|- H 2 = H 2 Sn0 3 , Stannic acid. 
Pb0 2 -f H 2 == H 2 Pb0 3 , Plumbic acid. 

CARBON occurs free in its three allotropic forms, diamond, graphite, 
and coal ; combined in carbonates and in all animal and vegetable 
substances. All its forms are probably traceable to organized life. 

Diamond. — Geological history unknown; transparent crystalline 
body of great brilliancy; hardest substance known. Used as a gem 
and for cutting glass, etc. 

Graphite (to write). — Owing to its resemblance to lead it has been 
called black lead or plumbago ; almost pure carbon. Used for pen- 
cils, crucibles, stove polish, etc. 

Coal. — Mineral coal is a black substance, compact in texture, the 
remains of vegetable life of past ages. Charcoal is obtained by burn- 
ing heaps of wood with a limited supply of air. The volatile con- 
stituents pass off, leaving the carbon as a light, porous substance, 
retaining the form and structure of the wood. Animal charcoal is 
made by heating animal matters in closed iron retorts. Charcoal, 
especially animal, is a valuable absorbent of odorous gases * and 
coloring matters.f 

Properties. — Free carbon is solid at all temperatures, and insoluble 
in all menstrua. Ordinarily, free carbon is unaffected by chemical 

* Experiment. — Fill a test-tube with ammonia gas over mercury (Fig. 29). 
Introduce a piece of charcoal recently heated. The gas is absorbed as is 
shown by the rapid rise of the mercury. 

f Experiment. — To a solution of indigo, cochineal, or potassium perman- 
ganate or beer in a flask, add some animal charcoal, shake up and filter. The 
filtrate is colorless, and in case beer is used it has also lost its bitter taste. 



PART I. — INORGANIC CHEMISTRY. 



57 



Fig, 




agents, but at high temperatures it surpasses all other elements in its 
avidity for O. Hence it is used to separate the metals from their 
oxides.* 

Carbon Monoxide — CO — occurs 
whenever carbon is burned with an 
insufficient supply of air, as in anthra- 
cite stoves and furnaces, and in coal 
gas, but never occurs in nature. 

Prepared in the laboratory by heat- 
ing oxalic acid, or potassium ferrocya- 
nide, with sulphuric acid. 

Properties. — Colorless, odorless, 
tasteless gas ; burns with a pale blue 
flame ; very poisonous, combining with 
the coloring matter of the blood cor- 
puscles, and destroying their oxygen- 
carrying power. Artificial respiration 
is of little use. Transfusion of blood 
is the most promising treatment. After 

death the blood remains scarlet. The sources of danger are open 
charcoal fires, defective draught in stoves and chimneys, and illu- 
minating gas escaping into bed-rooms. 

Carbon Dioxide — C0 2 . 

C0 2 + H 2 = H^C0 3 — Carbonic acid. 

Occurs sparingly (.0004) in the atmosphere, as a result of animal 
respiration, vegetable decay, and combustion. Plants absorb it, 
appropriating the carbon and returning the oxygen to the air. 

It often accumulates in cellars, beer-vats, wells, etc., where it is 
called choke-damp. 

Prepared by burning carbon, but most conveniently in the labora- 
tory by decomposing a carbonate with an acid. 

CaC0 3 + 2HCI = CaCl 2 + H 2 + C0 2 . 

Physical Properties. — Transparent, colorless gas, of a pungent odor 

* Experiment. — Into a slight depression in a piece of charcoal lay some 
metallic oxide — e.g., lead oxide — heat with a blow-pipe. The oxide is 
reduced by the heated charcoal around it, and globules of the metal appear 
which coalesce into a bright button. 

5 



58 



ESSENTIALS OF CHEMISTRY. 



and sour taste. One and a half times as heavy as air.* Water dis- 
solves its own volume. Soda-water is only a solution of this gas 
under pressure.! 

Fig. 30. 




Making CO. 

Chemical Properties. — Neither burns nor supports combustion. J In 
water it exists as carbonic acid — H 2 C0 3 . On attempting to concen- 



* Experiments. — To show the weight of carbon dioxide : (1) Pour it from 
one vessel to another. (2) Blow soap bubbles and allow them to fall into a 
wide vessel containing this gas. As soon as they reach the surface of the gas 
they stop and float upon it. (3) Pour a large beakerful of the gas into a light 
pasteboard box that has been balanced on a pair of scales. The box will at 
once descend. This gas accumulating in wells may be bailed in buckets, and 
tested by being poured upon a lighted candle. 

f That water will dissolve a greater quantity of carbon dioxide under pres- 
sure is shown by the rapid evolution of the gas whenever a bottle of soda or 
other carbonated water is opened and the pressure thereby removed. 

% Set a candlestick, holding several lighted tapers at different heights, in a 
large jar. Carbon dioxide is introduced at the bottom, and extinguishes the 
tapers one by one as the vessel fills up to their levels. 



PART I. — INORGANIC CHEMISTRY. 



59 



Fig. 31. 



trate this dilute solution the acid decomposes again into water and 
C0 2 ; hence wet litmus reddened by it becomes blue again on dry- 
ing. 

Tests. — (1) The gas (15 per cent, and over) extinguishes a flame; 
(2) precipitates lime-water ;* (3) carbonates effervesce on adding a 
strong acid. 

Physiological. — If the gas be undiluted, death is immediate from 
spasm of the glottis. If somewhat dilute (15 to 30 per cent.) there is 
loss of muscular power, anaesthesia, and death without a struggle. If 
quite dilute (5 to 10 per cent.) headache, giddiness, muscular weak- 
ness, and sometimes vomiting and con- 
vulsions occur. 

The effects are more serious if the C0 2 
comes from combustion or respiration, 
because of the removal of oxygen and 
the admixture of the deadly CO and ani- 
mal exhalations. 

Treatment. — Fresh air, artificial respira- 
tion, and stimulation. The preventive is 
ventilation. 

Ventilation. — More than 7 parts of 
C0 2 in 10,000 of air is oppressive. Taking 
this as the maximum impurity allow- 
able, 3000 cubic feet of fresh air per hour 
is needed by each person, and more in 
case of disease or when lamps are burn- 
ing. To secure this in a room containing 1000 cubic feet (10 X 10 X i°) 
the air must be changed three times an hour. This would give a 
draught not uncomfortable or injurious. If the draught be properly 
distributed, a breathing space of 500 cubic feet changing six times an 
hour would be unobjectionable. Ventilation may be secured in two 
ways, by diffusion and by draught. 




* Experiment. — Two Wolff bottles are half filled with lime-water and 
arranged as in Fig. 31. Placing the rubber tube in his mouth, the operator can 
inspire through one bottle and expire through the other. The small amount 
of carbon dioxide in the inspired and the larger amount in the expired air is 
shown by a white precipitate, slight in the one and dense in the other bottle. 



6o 



ESSENTIALS OF CHEMISTRY. 



Fig. 




Diffusion. — Gases mingle more rapidly, liquids more slowly, to 
make a mixture of uniform density. 

When two gases of different densities are sepa- 
rated by a porous partition, they mingle, the lighter 
passing through more rapidly than the heavier, the 
rapidity being in inverse ratio to the square roots 
of their densities.* 

This diffusion is more active in winter than in 
summer, because of the greater difference in den- 
sity of the warm air within the house and the cold 
air without. Damp walls are unhealthful mainly 
because being no longer porous they prevent this 
diffusion. 

Cyanogen — CN or Cy. Univalent because N m 
can satisfy only three valences of C IV . A com- 
pound negative radical resembling in its chemical 
behavior the elements of the chlorine group. 

Prepared by strongly heating mercuric cyanide.f 

Hg(CN) 2 = Hg + 2CN. 

A colorless gas, smelling like peach kernels. 
Burns with a peach -blossom flame ; unites with 
metals to form cyanides, the most important 
being — 

Hydrocyanic Acid — H(CN), or HCy — (Prussic 
Acid, Hydrogen Cyanide). — Occurs in bitter al- 
monds, cherry-laurel water, etc. 

Properties. — Colorless liquid, having an odor like peach kernels. 




* Experiment. — Cement a porous earthenware battery cup at its open end 
to the top of a funnel tube, the end of which dips into a bottle of colored 
water. Support on a stand, as in Fig. 32. Bring down over the cup an inverted 
bell jar of hydrogen. The light H diffuses so much faster into the cup than 
the air diffuses out of it, that bubbles of gas escape rapidly through the water. 
Remove the bell jar and the conditions are reversed. The H now diffuses so 
rapidly out of the cup that the water is sucked up the tube. 

f If mercuric cyanide cannot be obtained, a mixture of two parts of thor- 
oughly dried potassium ferrocyanide and three parts mercuric chloride may 
be used. 



PART I. — INORGANIC CHEMISTRY. 6 1 

For medical purposes only a dilute (2 per cent.) solution is used, and 
the dose is from two to five drops. * 

Toxicology. — All the cyanides are very poisonous. One drop of the 
pure acid produces immediate death, and three grains of potassium 
cyanide kills in a few minutes. The respiratory centres are paralyzed, 
and the victim falls and dies in convulsions. Poisoning is liable to 
occur from handling the acid or the cyanides, which are largely used 
in the arts, or from eating vegetable products, e. g. peach and cherry 
seeds containing amygdalin, a substance easily decomposing into 
prussic acid and other products. Owing to the rapid action of the 
poison, antidotes are usually impracticable. Use artificial respiration 
and stimulate. If the patient survive an hour, the prognosis is good. 

Tests. — (1) Its odor; (2) silver nitrate — white precipitate soluble in 
boiling HNO3 ; (3) add ammonium sulphydrate, evaporate to dryness, 
and then add ferric chloride — a blood-red color. 

Cyanates. — Cyanic acid (HCyO) and ammonium cyanate (NH 4 - 
CyO) are the most interesting. The latter on being heated forms urea. 

Sulphocyanates are sulpho-salts corresponding to the cyanates 
(oxy-salts), and are good illustrations of the facility with which S forms 
series of compounds analogous to those of O. They, especially the 
potassium and sodium salts, are used as test reagents. 

Compound Cyanides. — Cyanogen shows a great tendency to 
form complex radicals, especially with iron ; as, ferrocyanogen 
[Fe II (CN) 6 I ] IV or (FeCy 6 ) IV , and ferricyanogen [Fe^CN)^ 1 or 
(Fe 2 Cy 12 ) vl . These two radicals contain ferrous and ferric iron re- 
spectively, and with hydrogen form acids known as hydro-ferrocyanic 
acid, H 4 FeCy 6 (tetrabasic), and hydro-ferricyanic acid, H 6 Fe 2 CNi 2 or 
H 6 Fe 2 Cy 12 (hexabasic) ; the salts of these acids are termed ferrocyan- 
ides and ferricyanides. 

Potassium Ferrocyanide — K 4 FeCy 6 — commonly called yellow 
prussiate of potash, and potassium ferricyanide — K 6 FeCy 12 — red 
prussiate of potash, are important test reagents. 

The carbon compounds will be further considered under the head 
of Organic Chemistry. 

SILICON (also called silicium) resembles carbon, and occurs in 
three allotropic forms corresponding to coal, graphite, and diamond ; 
most abundant element after oxygen. It exists in only a few com- 



62 ESSENTIALS OF CHEMISTRY. 

pounds, but they constitute the larger part of the earth's crust. Its 
principal compound is — 

Silicic Oxide — Si0 2 — occurring as flint, sand, rock-crystal, etc. ; 
with water it forms silicic acid. Clay, soapstone, asbestos. 

Silicates of aluminium and magnesium are very abundant, as clay, 
soapstone, asbestos, etc. Glass is a mixture of several silicates, usu- 
ally of sodium, calcium and sometimes lead. It is made by melting 
sand (Si0 2 ) with the carbonates or oxides of the metals. The addition 
of certain metallic oxides gives color ; e.g., cobalt gives a blue, manga- 
nese an amethyst, and copper a ruby. If the glass consist of only an 
alkaline silicate (e.g., sodium), it is soluble or water-glass, which is 
largely used in surgical dressings. 

TIN. — A bluish-white malleable metal,* not corroded by air or 
water ; hence used to form a protective coating for iron and copper. 
Tin-ware is usually sheet-iron coated by being dipped into molten 
tin. Tin alloyed with lead is easily dissolved, and may cause lead- 
poisoning. 

Tin-foil (thin laminae of tin) is used in wrapping to exclude air and 
moisture. Tin enters into the composition of a great many alloys. 
Powdered tin is sometimes used as an anthelmintic. 

* The Metals. — Occurrence. — Some, as gold and copper, occur free, but 
most of them are found combined with non- metallic elements, especially sulphur 
and oxygen. 

Preparation. — If combined with sulphur the ore is roasted until the sulphur 
is burned out, leaving the metal as an oxide, which is then heated with carbon 
to remove the oxygen, thus : — 

ZnS + 3 = ZnO + S0 2 ; then, ZnO + C = CO + Zn. 

Physical Properties. — Very opaque, with a "metallic lustre" (in fine powder, 
a dull black) ; bluish-gray, varying between the pure white of silver and the 
dull blue of lead. Yellow gold and red copper are exceptions. In weight, 
varying between lithium, specific gravity 0.58, and platinum, specific gravity 
21.50. Most are solid, except mercury (liquid) and hydrogen (gaseous). All 
are absolutely insoluble. 

Chemical Properties. — Electro-positive, possessing great affinity for the non- 
metals and other electro-negative radicals. When two metals are fused together 
the product is an alloy. If one of the metals be mercury, it is called an amal- 
gam. Alloys are not chemical compounds, but mixtures, for the metals do not 
unite in definite proportions, and the alloy is not a new substance, but one with 
properties intermediate between those of its constituent metals. 

Used mostly in the arts. Of the fifty-five metals only about twenty-six, or 
rather compounds of these, enter the materia medica, and merit our notice. 



PART I. — INORGANIC CHEMISTRY. 63 

Tin forms two classes of compounds ; the stannous, in which the 
atom is bivalent, and stannic, in which the atom is quadrivalent. 
These are of importance to the chemist, but of little interest to the 
physician. 

LEAD. — Its principal ore is its sulphide (PbS), called galena. It 
is a soft, heavy, blue metal, very slowly acted upon by most sub- 
stances; hence used to make water-pipes and vessels that are exposed 
to corrosive liquids. # 

Water containing nitrates or nitrites (from organic matter) dissolves 
lead slightly ; but if it contains carbonates or sulphates, the lead is 
protected by. an insoluble coating of lead carbonate or sulphate. 

Lead enters into the composition of many alloys : as pewter, solder, 
shot, type-metal, etc. The quadrivalent compounds of lead are of so 
little importance that the term plumbic is applied to the bivalent 
compounds. 

Lead Oxide — PbO — Litharge. — A yellow substance, found native; 
made artificially by heating lead in the air. It is by treating this with 
the appropriate acid that most of the lead salts are prepared. When 
rubbed with oil it decomposes the glyceryllic ethers and combines 
with the fatty acids to form lead soaps, one of which, the oleate, is 
lead plaster, emplastrum plumbi , U. S. P. 

Lead Dioxide, or ptice lead, is a dark-brown powder, forming one 
of the constituents of red lead (Pb 3 4 or 2PbO.Pb0 2 ). 

Preparedly treating red lead with nitric acid to dissolve out the PbO. 

Lead Nitrate — Pb2N0 3 . 

Made: PbO + 2HNO3 = Pb2N0 3 + H 2 0. 

Ledoyeii s disinfectant fluid is a solution of Pb2N0 3 (one drachm to 
the ounce). It corrects fetid odors by neutralizing H 2 S and NH 4 HS. 

Lead Acetate — Pb(C 2 H 3 2 ) 2 , or PbAc 2 — Sugar of Lead. 

Made: PbO + 2HAc = PbAc 2 + H 2 0. 

Used in medicine more than any other lead salt. Its solution will 
dissolve considerable quantities of PbO, forming the solution of the 
subacetate of lead, the liquor plumbi subacetaiis, U. S. P., Goulard 's 
extract. It is astringent, and, like all the lead salts, sedative. Much 
used as a topical application in erysipelas, acute eczema, and other 
skin affections; and diluted {lead-water), it is used in conjunctivitis 
and other mucous inflammations. 



64 ESSENTIALS OF CHEMISTRY. 

The following insoluble salts may be made by precipitation from 
solutions of the preceding soluble ones: — 

Lead Chloride — PbCl 2 . — Made: Soluble lead salt added to a 
soluble chloride ; e. g, PbAc 2 + 2HCI = PbCl 2 + 2HAc. Slightly 
soluble in warm water, but in cold it is always precipitated from solu- 
tions of moderate strength ; hence classed with HgCl and AgCl as one 
of the three insoluble chlorides. 

Lead -Sulphate — PbS0 4 .— Forms as a white precipitate whenever 
a solution of a lead salt is added to a sulphate solution, thus : — 

PbAc 2 + ZnS0 4 = PbS0 4 + ZnAc 2 . 

Lead Carbonate — PbC0 3 — White Lead. 

Made : PbAc 2 + Na 2 C0 3 = PbC0 3 + 2NaAc. 

Commercially, it is made by some modification of the old Dutch 
method, which consists in covering bars of lead with the refuse of the 
wine-press and barn manure. The acetic fumes from the grape husks 
attack the lead, forming lead acetate, which is decomposed by the 
carbonic acid from the manure. The acetic acid thus liberated com- 
bines with another portion of lead, which is again precipitated by the 
carbonic acid, and thus the process continues until all the lead is 
consumed. 

Used for painting, but blackens when air contains H 2 S. 

Lead Sulphide — PbS — is formed as a black precipitate whenever 
a lead solution is treated with a soluble sulphide, as H 2 S or NH 4 HS. 

Lead Iodide — Pbl 2 . — A bright yellow precipitate on adding a 
soluble iodide to a lead solution ; as, — 

PbAc 2 + 2KI = 2KAc + Pbl 2 . 

Lead Chromate — PbCr0 4 . 

Made : PbAc 2 + K 2 Cr0 4 — PbCr0 4 + 2KAc. 

Under the name of chrome yellow it is used in painting. Of late it 
has been used to color food products. 

Tests for lead consist in forming precipitates of the foregoing in- 
soluble compounds. 

Physiological. — All the lead compounds are poisonous. Acute 
poisoning sometimes occurs from the ingestion of a single large dose 
of a soluble lead salt. The symptoms are those of gastric irritation. 
Treatment. Give MgS0 4 to form the insoluble PbS0 4 . 



PART I. — INORGANIC CHEMISTRY. 65 

The chronic form of lead intoxication, painter s colic, is purely 
poisonous, and is produced by the continued absorption of minute 
quantities of lead by the skin of those handling it, and by the lungs 
and stomachs of those living in painted apartments, or using food and 
drink from leaden vessels. There is impairment of digestion, consti- 
pation, blue line along the edge of the gums, colic, and paralysis, 
especially of the extensor muscles. Lead once absorbed is eliminated 
very slowly, having combined with the albuminoids, a combination 
which is rendered soluble by the administration of iodide of potas- 
sium. 

The treatment for chronic lead-poisoning is to give MgS0 4 , for the 
double purpose of overcoming the constipation and precipitating any 
lead remaining unabsorbed in the alimentary canal ; also KI to pro- 
mote the. elimination of that which is combined with the albuminoids. 
Alum is a favorite treatment, seeming to perform all accomplished by 
both the MgS0 4 and KI. The paralyzed muscles must be treated 
with electricity, so that when the lead is eliminated and the nerve 
influence returns, it may not find them degenerated past redemption. 



VI. Metals of the Alkalies. 

Hydrogen, H 1 

Lithium, Li 7 

Ammonium, (NHJ 18 

Sodium (Natrium), Na 23 

Potassium (Kalium), K 39.1 

Rubidium, Rb 85 

Cesium, Cs 133. 

Univalent ; very electro-positive (except H), so that when com- 
bined, unless it be with a strongly electro-negative (acidulous) radical, 
they form very alkaline compounds (hence the name). The positive 
affinities, as in the other groups, increase with the atomic weights. 
All their compounds are soluble. 

LITHIUM. — Sparingly but widely distributed in nature, especially 
in the waters of certain springs. Lightest of the solid elements. Its 
salts closely resemble those of sodium. 

Physiological. — Lithium urate being by far the most soluble com- 
pound of uric acid, salts of lithium, especially the carbonate, are given 



66 ESSENTIALS OF CHEMISTRY. 

to gouty persons to promote the elimination of uric acid, -which ac- 
cumulates in that disease. 

Test. — It colors the flame a beautiful carmine red. 

AMMONIUM. — When ammonia gas (NH 3 ) combines with an acid, 
it appropriates the basic hydrogen and forms a salt in which NH 4 is 
the positive radical ; e. g. : — 

NH 3 + HC1 = NH 4 C1, corresponding to KC1 or NaCl; 
NH 3 + HHO = NHJIO, corresponding to KHO or NaliO; 
NH 3 + HN0 3 = NH 4 N0 3 , corresponding to KN0 3 or NaN0 3 ; 
2NH 3 + H 2 S0 4 = (NH 4 ) 2 S0 4 , corresponding to K 2 S0 4 or N^SO^. 

This radical plays the 7'dle of a metal, like K and Na, and is called 
Ammonium. Does not exist uncombined, although Weyl claims to 
isolate it as a dark-blue liquid metal. * We can obtain it as an amal- 
gam by the reaction between sodium amalgam and ammonium 
chloridcf 

Ammonium Hydrate — NH 4 HO — Caustic Ammonia — is formed in 
solution whenever ammonia gas (NH 3 ) dissolves in water, thus : NH 3 
+ H 2 = NH4HO. It has been already stated that the watery solu- 
tion of a fixed substance is called a liquor ; of a volatile substance, an 
aqua. In like manner alcoholic solutions of fixed substances are 
called tinctures, and of volatile, spirits. There are four U. S. P. solu- 
tions of ammonia : — 

Aqua ammonia, • 10 per cent. 

Aqua ammonia fortior, 26 " 

Spiriius ammonia, 10 " 

Spii'itus ammonia aromaticus. 

* Experiment. — The supposed free ammonium. Sodio-ammonium is pre- 
pared by heating sodium in a sealed tube with ammonia gas. This is in turn 
heated with ammonium chloride in a sealed tube. A dark blue liquid, with 
metallic lustre, is obtained, but soon decomposes into ammonia gas and hydro- 
gen. 

I Experiment. — To some mercury in a test-tube add sodium, small bits at 
a time. On this sodium amalgam pour a strong solution of ammonium chlo- 
ride. Sodium chloride and ammonium amalgam are formed. 

(Na + Hg) + NH 4 C1 — NaCl + (NH 4 + Hg). 

The ammonium amalgam swells up and soon decomposes — (NH 4 -f~ H-g) = 
NH 3 -)- H -f- Hg — the gaseous NH 3 and hydrogen escape, and only the 
mercury remains. 



PART I. — INORGANIC CHEMISTRY. 6j 

In all these solutions NH 4 HO exists, but has never been isolated, 
because, whenever we attempt to evaporate the water or alcohol, the 
NH4HO decomposes into NH 3 -f- H 2 0. Ammonium hydrate is very 
alkaline. 

Ammonium Hydrosulphide — NH 4 HS — occurs in decomposing 
nitrogenous, sulphurized organic bodies. Made by saturating a solu- 
tion of NH4HO with H 2 S. A yellowish solution ; used as a test reagent. 

Ammonium Carbonate — (NH 4 ) 2 C0 3 . — Ammenii Carbonas, U. S. P. 
— Sal volatile — is prepared by heating a mixture of NH 4 C1 and chalk 
(CaC0 3 ) up to the temperature at which (NH 4 ) 2 C0 3 would be vola- 
tilized, when the following reaction will occur : — 

2NH 4 C1 -f CaC0 3 = CaCl 2 + (NH,) 2 C0 3 . 

(See Volatility, page 25.) Very prone to absorb C0 2 from the atmos- 
phere and become bicarbonate unless NH 4 HO be added. 

Other salts may be made by adding the appropriate acid to the 
carbonate or hydrate of ammonium. If we use the carbonate, we 
can tell when acid enough has been added by the cessation of effer- 
vescence. If the hydrate be used there is no effervescence, and our 
only guide is the point at which the solution becomes neutral in 
reaction. This is determined by the use of test papers. These are 
made of white, unsized paper, steeped in a blue vegetable pigment 
called litmus, which is reddened by acids and restored to its blue by 
alkalies. 

Physiological. — The hydrate and carbonate are alkaline irritants, 
like the corresponding K and Na compounds, though in less degree. 
They, moreover, give off NH 3 , which, though irritating to the respira- 
tory tract, is a valuable stimulant in fainting fits, etc. Two drachms of 
aqua ammoniae have killed. The treatment, as for all alkalies, is to 
give a dilute acid or some oil. 

Tests. — (1) An ammonium salt warmed with liq. potassas gives off 
NH 3 , recognized (a) by its odor, (b) its forming a white cloud of 
NH 4 C1 when a glass rod dipped in the HC1 is held over the vessel, 
and (c) its changing moist red litmus to blue. (2) Heat the dry 
ammonium salt and it volatilizes. 

SODIUM occurs very abundantly as sodium chloride, or common 
salt, from which almost all the sodium compounds are now obtained 



68 



ESSENTIALS OF CHEMISTRY. 



instead of from ashes of seaweeds, as formerly. The preparatio)i 
and properties of sodium and its compounds are so similar to those of 
potassium that we will omit their separate consideration. So much 
alike are the salts of the two metals that the choice between them is 
usually governed by considerations of economy, convenience, solu- 
bility, fashion, etc. On exposure to the atmosphere the sodium salts 
usually have a tendency to effloresce, while the potassium salts tend 
to deliquesce. 

Tests. — No good precipitant ; for all the compounds of sodium are 
soluble. However, the strong yellow color it gives a flame is a very 
delicate test ; in fact, too delicate, for it shows traces of sodium in 
almost everything. 



Fig. 33. 




Fig. 34. 




POTASSIUM occurs only in compounds. Prepared by heating 
one of its oxygen compounds with charcoal in an iron retort 
(K 2 C0 3 + 2C = 3CO + K 2 ). The metallic K distills over and is 
condensed in a flat receiver. 

Physical Properties. — Soft as wax ; lighter than water ; silvery 
lustre when freshly cut, but quickly tarnishes. 

Chemical Properties. — Intensely electro-positive ; hence it possesses 
great affinity for the non-metals ;* takes O from H 2 0, even as ice, f 
setting fire to the escaping H, giving the flame the violet color char- 
acteristic of K (Fig. 34). 



* Experiment. — Potassium inflames spontaneously when lowered into a jar 
of chlorine (Fig. 33). Warmed with iodine or dropped into bromine it 
explodes violently. This should be done under a tubulated bell jar, because 
the potassium is scattered in every direction. 

f Experiment. — Load a strong toy cannon with gunpowder. On the fuse 
lay a small bit of potassium. Touching it with a piece of ice fires the cannon. 



PART I. — INORGANIC CHEMISTRY. 69 

Potassium Carbonate — K 2 C0 3 . — Obtained as an impure solu- 
tion ("lye") by lixiviating the ashes of plants, especially forest trees. 
This, evaporated to dryness, forms " concentrated lye." This in 
turn, when purified, forms "pearl-ash," which is further purified for 
medicinal use. Sometimes made by burning cream of tartar and 
lixiviating the residue, hence called salts of tartar. A white semi- 
crystalline or granular powder. C0 3 being a weakly acidulous radi- 
cal, K 2 C0 3 is very alkaline, even caustic. 

Acid Salts. — Salts are formed by a metallic radical displacing the 
basic H of an acid. If all the H be displaced, the result is a normal 
salt, as, H 2 S0 4 + K 2 = K 2 S0 4 + H 2 . But if part of the basic H 
of the acid remains, it is called an acid salt, as H 2 S0 4 + K = 
KHS0 4 + H. Sometimes acid salts are called "bi " salts, because 
the proportion of the acidulous radical to the basylous is twice as 
great as in the normal ; e.g., KHS0 4 is called potassium bisulphate, 
because the proportion of the acidulous radical S0 4 to the basylous 
radical K is twice as great as in the normal sulphate, K 2 S0 4 . 

Potassium Bicarbonate — KHC0 3 . — Although an acid salt in 
constitution, it is alkaline in reaction, on account of the weakness 
of its acidulous radical. Made by passing C0 2 into a solution of 
K 2 C0 3 . The reaction is as follows : — 

K 2 CO s + H 2 + C0 2 = 2KHCO3. 

Potassium Bitartrate — KH (C 4 H 4 6 ) or KHT — Cream of Tar- 
tar. — Prepared similarly to the above, by adding tartaric acid to a 
solution of the normal tartrate, thus: K 2 T + H 2 T = 2KHT. It 
exists naturally in grape juice, and, being insoluble in an alcoholic 
menstruum, is precipitated on the sides of the wine casks whenever 
vinous fermentation sets in. This is its commercial source. 

Other Salts. — Most salts of K are made by treating the car- 
bonate with the appropriate acid, e.g. : — 

The chloride— K 2 CO s + 2HCI = 2KCI + H 2 + C0 2 . 
The sulphate— K 2 C0 3 + H 2 S0 4 = K 2 S0 4 + H 2 + C0 2 , etc. 

The decomposition is attended with an effervescence of C0 2 . It is 
the formation of this volatile compound that determines the reaction. 
(See Volatility, page 25.) 



JO ESSENTIALS OF CHEMISTRY. 

But the following salts are not made in this way : — 
Potassium Hydrate — KHO — Caustic Potash — maybe made ex- 
perimentally by the reaction of metallic K on water, thus : — 

H 2 + K = KHO + H. 
But made in the shops by boiling K 2 C0 3 with slaked lime, thus: — 
K 2 C0 3 + Ca2HO = CaC0 3 + 2KHO. 

The insoluble CaC0 3 (chalk) sinks to the bottom, and the KHO 
dissolves in the supernatant liquid, which when clear is poured off 
(decanted). This watery solution, if of proper strength (§j-Oj), forms 
" Liquor potassce, U. S. P." If this solution be evaporated to a syrupy 
consistence and poured into moulds, it forms the stick caustic potash. 
KHO is very alkaline, and a powerful cautery. 

Exposed to the air it absorbs C0 2 and forms carbonate : — 

2KHO + C0 2 == K 2 CO s + H 2 0. 
Potassium Iodide — KI : — 

6KHO + 61 = 5KI + KIO3 + 3H 2 0. 

The color disappears because the I goes to form colorless salts. 
Prepared thus, the KI is contaminated with KI0 3 (K-Iodate).* But if 
the mixture be strongly heated the 3 is driven off and the KI alone 
remains. The addition of charcoal facilitates the removal of the 3 . 

Potassium Bromide — KBr — may be made similarly to the above. 

Sodio-Potassium Tartrate — NaKT — Rochelle Salt, — A neutral 
salt made by boiling acid potassium tartrate with sodium bicarbonate. 

KHT + NaHC0 3 = NaKT + H 2 + C0 2 . 

This is the reaction that occurs in baking with cream of tartar baking 
powders. 

Potassium Hypochlorite — KCIO. — Made by passing chlorine into 
a cold solution of KHO. Yields free chlorine. The ordinary bleach- 

* Experiment. — The presence of KI0 3 in a commercial specimen of KI 
may be recognized by boiling a little starch in a test-tube, dissolving a crystal 
of the suspected salt, and then adding a few drops of a strong solution of tar- 
taric acid; if KI0 3 be present, I will be liberated, and a blue color struck with 
the starch. 



PART I. — INORGANIC CHEMISTRY. J I 

ing solutions (Labarraque's Solution or Javelle water) are solutions of 
impure sodium or potassium hypochlorite. 

Tests for Potassium. — (i) If the suspected solution be concentrated, 
add H 2 T and get a precipitate of KHT * (2) Platinic chloride (PtCl 4 ) 
gives a yellowish precipitate. But the PtCl 4 is very costly, and all the 
potassium compounds so soluble that the above tests are but little 
used. The most convenient is the (3) flame test : dip the end of a 
clean platinum wire in the suspected solution, and hold in the color- 
less Bunsen or alcohol flame and notice the violet color. 

CESIUM AND RUBIDIUM.— Rare metals, occurring in small 
quantities with potassium. Discovered* in i860 by means of the spec- 
troscope, and named from the colors of their lines in the spectrum 
(ccesius, sky blue, and rubidus, dark red). Of no medical interest as yet. 

Analytical. — To determine whether a salt be a compound of K, Na, 
NH 4 , or Li, heat samples of each ; the one that volatilizes is the salt 
of NH 4 . Confirm this by boiling with KHO and getting the odor of 
ammonia. To the other three salts apply the flame tests, getting the 
violet for K,f yellow for Na, and carmine for Li. 



VII. Metals of the Alkaline Earths. 

Magnesium, Mg 24 

Calcium, Ca 40 

Strontium, Sr . . . • . 87.5 

Barium, Ba 137 

Bivalent ; their oxides and hydrates are very alkaline, but of an 
earthy character. Their positiveness or basicity, as in other groups, 
is in the order of the atomic weights. Their carbonates are decom- 
posable by heat and insoluble in water, unless it contains H 2 C0 3 in 
solution. Their sulphates increase in solubility from the insoluble 
barium salt to the very soluble magnesium sulphate. 

MAGNESIUM. — Never free ; abundant in magnesian limestone 
(CaC0 3 .MgC0 3 ). Asbestos, meerschaum, and soapstone are native 

*The addition of alcohol renders the test much more delicate. 

f The delicate violet of K may be masked by the intense yellow of Na, but 
can be seen if observed through a piece of blue glass, a medium that absorbs 
the yellow light. 



72 ESSENTIALS OF CHEMISTRY. 

silicates. Most natural waters contain its salts. Silvery white metal ; 
burns with a brilliant white light, rich in chemical rays, and used in 
photographing caves and other dark places. 

Magnesium Sulphate — MgS0 4 — occurs in the waters of various 
springs, as those at Epsom ; hence often called Epsom salts. Made 
artificially from the native carbonate, thus : — 

MgC0 8 + H 2 S0 4 = MgSO, + (H 2 + CO a ). 

White, crystalline, soluble salt of a nauseous bitter taste. It is a 
popular purgative. The nauseous taste and griping may be obviated 
by adding aromatics, acid, sulphate of iron (as in Crab Orchard salts) 
or by free dilution. 

Magnesium Citrate is the most pleasant of the saline purgatives. 
Usually given as the liquor magnesii citratis, which is prepared by 
adding a solution of citric acid to MgC0 3 , and bottling immediately to 
retain the C0 2 , 

Magnesium Carbonate — MgC0 3 — occurs native. For medicinal 
purposes it is prepared by precipitation, thus : — 

MgS0 4 + Na 2 C0 3 = Na 2 SC\ + MgC0 3 . 
Similar to chalk in its physical and chemical properties. 

Magnesium Oxide — MgO — Magnesia. Made like CaO, by heat- 
ing the carbonate. 

MgCO s = MgO + C0 2 . 

Insoluble and tasteless (earthy), but its alkalinity is shown by its 
turning moist red litmus paper blue when the solid MgO is dropped 
upon it. 

Magnesium Hydrate — Mg(HO) 2 . — Formed by precipitating a 
magnesium solution with potassium or sodium hydrate. Insoluble in 
water, but, like other salts of magnesium, soluble in the presence of 
ammonium compounds with which they form double salts. Suspended 
in water, it is called milk of magnesia. 

Magnesium Phosphates. — These resemble the calcium phosphates 
and are associated with them in the body, though in small quantity. 
The ammonio-magnesium phosphate (MgNH 4 P0 4 ) is precipitated 
whenever a soluble phosphate in neutral or alkaline solution finds 
itself in presence of an ammonium salt, as occurs in the alkaline fer- 
mentation of urine. 



PART I. — INORGANIC CHEMISTRY. 73 

Physiological. — Magnesium oxide and hydrate being alkaline and 
tasteless, are popular antidotes for acids. These and the carbonate 
are given to correct acid conditions of the digestive tract, and com- 
bining with the acids they form soluble salts that are laxative. 

CALCIUM. — Never free, but its compounds are very abundant, as 
limestone, gypsum, etc. Calcium salts are necessary to animal life, 
the teeth and bones consisting mainly of calcium phosphate. 

Calcium Chloride — CaCl 2 . 

Made : CaC0 3 + 2HCI = CaCl 2 + H 2 + C0 2 . 

A white salt ; very avid of water and deliquescent ; used to dry 
gases. 

Calcium Carbonate — CaC0 3 . — Abundant as limestone, marble, 
corals, chalk, and shells of the Crustacea, mollusks, etc. Chalk con- 
sists of microscopic shells. Precipitated chalk is made by adding a 
soluble carbonate to a soluble calcium salt, as : — 

Na 2 C0 3 + CaCl 2 = 2NaCl + CaC0 3 . 

The precipitate (CaC0 3 ) may be separated from the CaCl 2 in solu- 
tion, by — 

(a) Filtration. — Pouring the mixture into a cone of filter paper placed 
in a funnel, when the water with the dissolved salt will pass through, 
leaving the insoluble portion (the precipitate) on the filter, (b) Decan- 
tation. — Allowing the precipitate to settle to the bottom, and pouring 
off the clear fluid. In either case the precipitate may be washed from 
any remaining CaCl 2 by adding pure water and repeating the process. 

Calcium Oxide — CaO — Lime, quicklime ; calx, U. S. P. — A white 
solid ; made by heating limestone in rude furnaces called kilns. 

CaC0 3 = CaO + C0 2 . 

When water is added to CaO there is a violent chemical union, great 
heat is evolved, and a hydrate is formed, thus : — 

CaO -f H 2 = Ca2HO. 

Calcium Hydrate — Ca2H O— Slaked lime.— A white, odorless 
powder; very slightly soluble in water, less than one grain to the 
ounce, but enough to give " lime-water " {liquor calcis, U. S. P.) a 



74 ESSENTIALS OF CHEMISTRY. 

decidedly alkaline taste and reaction. The presence of sugar greatly 
increases its solubility (Jig. calcis saccharatus, Br.). 

Chlorinated Lime — Chloride of time, bleaching powder, calx 
chlorata, U. S. P. — is a mixture of chloride of calcium (CaCl 2 ) and 
calcium hypochlorite (Ca2C10). It is made by passing chlorine gas 
over slaked lime until it ceases to be absorbed. It is white, moistens 
on exposure to the air, absorbing C0 2 and giving off CI. It is em- 
ployed as a source from which to get a gradual supply of chlorine for 
disinfecting and bleaching purposes. 

Calcium Sulphate — CaS0 4 — occurs negative, as gypsum, which, 
when heated, loses its water of crystallization and forms a white amor- 
phous powder called plaster- of- Paris. If this plaster be mixed with 
water enough to form a creamy liquid, it will recrystallize or "set" 
into a hard compact mass. Much used in surgery to make casts to 
hold broken limbs in position. Very slightly soluble in water. 

Calcium Phosphate — Ca 3 (P0 4 ) 2 .— It is the most abundant mineral 
ingredient of the body ; in every tissue and fluid, especially the teeth 
and bones, to which it gives hardness and rigidity. A white tasteless 
powder, soluble in dilute acids. Dissolved by lactic acid, it is given 
as syrupus calcii lactophosphatis, U. S. P., in scrofula, rickets, and 
other diseases of defective nutrition. 

Calcium Oxalate — CaC 2 4 , or CaOx — occurs in the juices of some 
plants and in the urine. Obtained as a fine white crystalline powder 
when a soluble oxalate is added to a calcium solution. Insoluble in 
water or acetic acid, but soluble in the mineral acids. 

Hard Waters are such as contain mineral matters, especially 
calcium (lime) compounds. Often water, in passing through the 
soil, becomes highly charged with carbonic acid, and dissolves con- 
siderable amounts of CaC0 3 , and is hard. This is called temporary 
hardness, because on exposure or boiling, the carbonic acid is driven 
off, the CaC0 3 is precipitated, and the water becomes soft. The solu- 
bility of CaS0 4 does not depend on the presence of carbonic acid, 
and boiling will not precipitate it. So water impregnated with CaS0 4 
is said to be permanently hard. Drinking-water should contain a 
small quantity of lime ; but very hard water impairs digestion. Hard 
water is unfit for washing, because the soluble alkali soap reacts with 
the lime salt to form an insoluble lime-soap. 



PART I. — INORGANIC CHEMISTRY. 75 

STRONTIUM. — Of little importance, except that its nitrate is used 
in pyrotechny to make the red light.* 

BARIUM. — Of little interest to the medical student, except that its 
compounds are poisonous. Barium sulphate is very insoluble ; hence 
(i) the antidote of barium is some soluble sulphate, and (2) barium 
solutions (nitrate and chloride) are delicate tests for sulphates, and 
vice versa. (See Insolubility \ page 26.) Barium gives the flame a 
green color ; hence used (nitrate) in pyrotechny to make the green 
or Bengal light.f 

Analytical. — To determine whether a solution be one of barium, 
calcium or magnesium : Add potassium chromate ; a precipitate 
indicates barium. If no precipitate, add ammonium chloride and 
then ammonium carbonate ; a precipitate indicates calcium. If no 
precipitate, add sodium phosphate ; a precipitate indicates magnesium. 

VIII. Metals of the Earths. 

Boron, . B 11 

Aluminium, Al 27 

Scandium, Sc .... 44 

Yttrium, Y 92 

Lanthanum, La 139 

Cerium, • . . . Ce 141 

Didymium, D 145 

Samarium, Sm 150 

Erbium, E 168 

Ytterbium, Yb 173 

Trivalent, though in compounds two atoms go together, forming a 

* Red Fire : Strontium nitrate, 800 grains; sulphur, 225 grains; potassium 
chlorate, 200 grains, and lampblack, 50 grains. 

f Green Fire : Barium nitrate, 450 grains ; sulphur, 150 grains; potassium 
chlorate, 100 grains, and lampblack, 25 grains. 

For lecture-room experiments the following, without sulphur, are preferable : 

Green Fire :• Two parts barium nitrate, two parts potassium chlorate, and 
one part ground shellac. 

Red Fire : Two parts strontium nitrate, two parts potassium chlorate, and 
one part ground shellac. 

The ingredients should be dry, powdered separately, and mixed with as 
little friction as possible. 



j6 ESSENTIALS OF CHEMISTRY. • 

sexivalent radical, as A1 2 C1 6 . Boron is so weakly positive that it is a 
non-metal. Aluminium is the most important member of this group, 
the others being rare metals associated with it in various minerals. 
Their oxides and hydrates are of a neutral or earthy character. 

BORON occurs as a constituent of boracic acid and borax (sodium 
borate, U. S. P.). Has two allotropic forms, amorphous and crystal- 
line, corresponding to coal and diamond. Forms only one oxide 
(B 2 3 ), which, combining with water, forms an acid : — 

B 2 3 + 3H 2 = H 6 B 2 6 = 2H 3 B0 3 — Boric acid. 

Boric or Boracic Acid occurs as pearly scales, soluble in water ; 
feebly acid ; an unirritating antiseptic. Boiled with glycerine it was 
sold as boroglyceride, or mixed with borax as rex mag?tus to preserve 
foods, especially milk and meats. 

Test. — Compounds of boron, especially when moistened with sul- 
phuric acid, color the flame green. 

ALUMINIUM. — Never found free, but in the abundance and dis- 
tribution of its compounds it ranks next to oxygen and silicon— third 
among the elements and first' among the metals. Isolated with 
difficulty, and therefore costly. Bluish-white metal, ductile and very 
light ; does not tarnish in the air. With copper it forms a golden- 
yellow alloy, known as aluminium bronze. 

Aluminium Chloride — A1 2 C1 6 . — Prepared industrially in the manu- 
facture of aluminium. A soluble, astringent salt. It absorbs and 
combines with H 2 S, PH 3 , and NH 3 . An impure solution is sold as a 
disinfectant under the name chloralum. 

Aluminium Sulphate — AL3SO4. — Made by treating white clay 
with H 2 S0 4 . It has properties similar to the above. 

Alum — Alumen. — An alum is a double sulphate of a trivalent and 
a univalent radical. Its constitution may be expressed thus : — 

R 2 m 3S0 4 .R 2 r S0 4 , or 2R III R I 2S0 4 . 

The trivalent radical (R m ) may be Al, Fe, Cr, or Mn. The uni- 
valent radical (R 1 ) may be K, Na, NH 4 , etc. So, by different com- 
binations of these radicals a variety of alums may be formed. The 
old potash alum (A1 2 3S0 4 .K 2 S0 4 ) is giving place in the arts to the 
cheaper ammo7iiu7n alum (A1 2 3S0 4 .(NH 4 ) 2 S0 4 ). The ammonio -ferric 



PART I. — INORGANIC CHEMISTRY. JJ 

alum (Fe 2 3S04.(NH4)2S0 4 ) is also much used in medicine. Burnt 
alum, alumen exsiccatum, is a white amorphous powder obtained by 
heating alum until its water of crystallization is driven off. Alum, 
like other salts in which the acidulous radical predominates, is astrin- 
gent ; burnt alum, on account of its avidity for water, is a mild 
escharotic. 

Aluminium Silicates. — Very abundant, as granite, clay, sand, etc. 
Clay is usually of a reddish or brown color from admixture of oxides 
of Fe, etc. Pure white clay {kaolin) is used in the arts to make 
porcelain, and in medicine as a vehicle for the external application 
of acids, etc. 

CERIUM is a rare metal. One of its salts, the oxalate, is used as 
a sedative to irritable stomachs, especially in the vomiting of preg- 
nancy. When pure it is a very efficient remedy ; but the commercial 
article is liable to contain salts of lanthanum, didymium, and other 
allied metals. 

The other members of this group possess little interest for the 
medical student. 



IX. The Zinc Group. 

Zinc, Zn 65.2 

Cadmium, Cd 112 

Bivalent ; bluish-white metals, closely allied in sources and prop- 
erties. 

ZINC. — When heated in air, zinc burns with an intense bluish- 
white light, forming clouds of oxide. It tarnishes quickly in air or 
water, but becomes coated with a film of oxide that protects it from 
further corrosion. Iron coated with zinc ("galvanized iron") will 
withstand exposure to the weather an indefinite time. Alloyed with 
copper, zinc forms brass. Pure H 2 S0 4 is unaffected by pure zinc or 
zinc coated with mercury (amalgamated), unless it form a galvanic 
circuit.* Commercial zinc is rapidly attacked by most acids. 

* Experiment. — Into a large test-tube containing bits of zinc pour dilute 
sulphuric acid; there is a prompt effervescence of hydrogen. Add a little 
mercury, and agitate; the action ceases. Drop in a piece of copper; it begins 
a^ain. 



78 ESSENTIALS OF CHEMISTRY. 

Zinc Sulphate — ZnS0 4 — White Vitriol — is made thus : — 

Zn + H 2 S0 4 = ZnS0 4 + H 2 . 

White, soluble salt, resembling MgS0 4 in appearance ; astringent and 
emetic. 

Zinc Chloride — ZnCl 2 . — Made : Zn + 2HCI = ZnCl 2 + H 2 . A 
white deliquescent salt ; strongly astringent ; severe caustic. Used 
as an injection to preserve anatomical subjects. 

Each of the following mixtures forms a hard, white mass, used for 
filling teeth : — 

(a) A strong solution of zinc chloride with zinc oxide. 

(&) A strong solution of magnesium chloride with magnesium oxide. 

(c) Zinc oxide with phosphoric acid (zinc phosphate). 

Zinc Carbonate — ZnC0 3 — is a white, insoluble powder made by 
precipitation : — 

ZnS0 4 + Na 2 C0 3 = N^SO^ + ZnC0 3 . 

Used in the arts (zinc white) in place of lead carbonate, for it is 
not blackened by H 2 S ; in medicine as a dusting powder for excori- 
ated surfaces, and in ointment. 

Zinc Oxide — ZnO — is prepared either by burning metallic zinc* or 
heating the carbonate, ZnC0 3 = ZnO + C0 2 . 

It is a yellowish-white powder, used externally in ointment; inter- 
nally as a tonic and astringent, especially in the night-sweats of 
phthisis and diarrhoea of children. 

Zinc Sulphide — ZnS — is precipitated whenever a solution of a zinc 
salt is added to the solution of a soluble sulphide, unless the solution 
be acid in reaction. It is the only white sulphide, therefore a test for 
zinc. 

Poisoning. — All the salts of zinc that are soluble in the digestive 
fluids act as irritant poisons. Sodium chloride and organic acids dis- 
solve metallic zinc, therefore food kept in galvanized iron vessels is 
more or less poisonous, especially since commercial zinc usually con- 



* Experiment. — Place bits of zinc in a hessian crucible and heat strongly 
over a triple burner. The metal is volatilized, and the vapor igniting burns 
with an intense bluish-white flame, yielding white flakes of zinc oxide, the 
lana philosophica (philosopher's wool) of the older chemists. 



PART I. — INORGANIC CHEMISTRY. 79 

tains traces of arsenic. For this reason articles intended for toxico- 
logical analysis should never be kept in jars with zinc caps. 

CADMIUM resembles zinc in its properties and uses, except that 
its sulphide is yellow and insoluble in acid solutions. 



X. The Iron Group. 

Chromium, . . Cr 52.2 

Manganese, Mn 55.0 

Iron, Fe 56.0 

Cobalt, Co 58.8 

Nickel, Ni 58.8 

These are hard metals and all more or less magnetic. 

By a variation in valence they form two classes of compounds : 
One in which the atom is bivalent, as in ferrous chloride (FeCL) ; the 
other in which the atom is trivalent, as in ferric chloride (Fe 2 Cl 6 ). With 
oxygen they form acidulous radicals, which form the chromates, man- 
ganates, and ferrates, with the stronger bases. 

CHROMIUM. — So named because all its compounds are colored. 
The metal is of but little use. Its compounds are of great importance 
to the chemist and of considerable utility in the arts, but few are used 
in medicine. 

Chromium Trioxide — Cr0 3 — is made by treating a strong solution 
of potassium bichromate with sulphuric acid, thus : — 

K 2 Cr 2 7 + H 2 S0 4 = K 2 S0 4 + H 2 Cr0 4 + CrO s . 

The Cr0 3 separates in crimson prisms. It is a powerful oxidant and 
a caustic. Sometimes improperly called chromic acid. 

Chromates. — The principal ones are potassium chromate, K 2 Cr0 4 , 
a valuable test reagent, and lead chromate, PbCr0 4 , a yellow pig- 
ment. 

Bichromates are not regular acid or bi-salts, but compounds of a 



80 ESSENTIALS OF CHEMISTRY. 

chromate and chromium trioxide. The most important of these is 
potassium bichromate, K 2 Cr 2 7 , or K 2 Cr0 4 .Cr0 3 . It forms large, red, 
soluble crystals. It is added to the sulphuric acid in batteries to 
oxidize* the nascent hydrogen. 

Chromates may be recognized by their color and by the yellow pre- 
cipitate on the addition of lead acetate. 

MANGANESE resembles iron in its properties. Used to alloy iron 
in the preparation of certain kinds of steel. Its most abundant ore 
is the 

Manganese Dioxide — Mn0 2 — Black Oxide of Manganese — an 
insoluble steel-gray powder that readily gives up its extra atom of O. 
Used in large quantities in the preparation of chlorine and oxygen 
gas. 

Manganous Sulphate — MnS0 4 . 

Mn0 2 + H 2 S0 4 = MnS0 4 + H 2 + O. 
A soluble, rose-colored salt. 

Manganous Sulphide — MnS — is precipitated whenever a solution 
of a salt of manganese is treated with NH 4 HS. It is the only flesh- 
colored sulphide, hence its formation is a test of manganese. 

Manganates. — If a mixture of KHO, KC10 3 , and Mn0 2 be heated 
together, there results a green mass of potassium manganate, K 2 Mn0 4 . 
If this be dissolved in distilled water, it forms a green solution, which, 
on boiling, or even standing awhile, is changed to a purple, due to 
the formation of potassium permanganate, K 2 Mn 2 8 . 

The permanganate f gives up its oxygen so readily to organic matter, 

* Experiments. — The oxidizing action of the chromic salts can be shown - 
in a number of reactions, (a) Any organic substance, as sugar, oxalic acid, or 
a chip of wood, boiled in the sulphuric acid and bichromate mixture, is oxid- 
ized, disappearing completely, with evolution of carbon dioxide, (b) Rinse 
out a beaker with strong alcohol, and then drop in a few crystals of chromic 
acid. The thin layer of alcohol is ignited with the odor of aldehyde. (c) 
Pour a few drops of absolute alcohol on the wick of a spirit lamp, and lay on 
several crystals of chromic acid. It ignites. 

f Experiment. — Powdered potassium permanganate treated with sulphuric 
acid gives off ozone. (See page 19.) So powerful an oxidizer is this mixture 
that alcohol, ether, benzol, carbon disulphide, flowers of sulphur, tannin, etc., 
are ignited on contact with it. 



PART I. — INORGANIC CHEMISTRY. 8 1 

at the same time losing its purple color, that it is used as a test for 
organic impurity in water and as a disinfectant. 

Physiological. — Associated with iron (i to 20), manganese is a normal 
constituent of the blood corpuscles ; hence its preparations, like those 
of iron, are blood tonics. Valuable in amenorrhcea. 

IRON occurs abundantly as oxide, carbonate, and sulphide ; occa- 
sionally free. 

Preparation, — The carbonate or sulphide is first roasted until con- 

Fig. 35. 




Making Reduced Iron. 



verted into oxide. The oxide is heated in a blast furnace with coal 
and fluxes (limestone and silicates). The carbon of the coal removes 
the oxygen from the iron, which melts and sinks beneath the melted 
fluxes. The fused metal is then drawn off into furrows in the sand 
called pigs. This is cast iron, containing 4 or 5 per cent, of carbon. 
Wrought iron contains little or no carbon, and steel an intermediate 
amount. 

Properties. — A bluish-gray metal, sp. gr. 7.5 ; rusts (oxidizes) when 
exposed to moist air, or water containing air. 

Reduced Iron — Ferritin Redactuni, iron by hydrogen, Quevenne's 



82 ESSENTIALS OF CHEMISTRY. 

iron. — It is prepared by heating ferric oxide nearly to redness in a 
tube through which hydrogen is passed : — 

Fe 2 3 + H 6 = Fe 2 + 3 H 2 * 

It is a very fine, dark gray powder, which, if good and fresh, will 
ignite on contact with a lighted taper and burn with a red glow ; f pre- 
scribed in pill form. 

CHLORIDES. 

Ferrous Chloride — FeCl 2 . — Made by adding iron to hydrochloric 
acid until effervescence ceases, thus : — 

Fe + 2HCl=FeCl 2 + H 2 . 

Like most ferrous salts, it is green and prone to oxidize with the forma- 
tion of ferric compounds. 

Ferric Chloride — Fe 2 Cl 6 — is made by first forming the ferrous 
chloride as above, and then adding nitric and hydrochloric acids. 
The nascent chlorine evolved by the nitro-hydrochloric acid converts 
the ferrous into ferric chloride, thus : — 

6FeCl 2 + 6HC1 + 2HN0 3 == 3Fe 2 Cl 6 + N 2 2 + 4H 2 0. 

The liq. ferri chloridi, U. S. P., is the aqueous solution. This, when 
diluted with alcohol, forms the tinct. ferri chloridi, U. S. P. If citrate 
of potassium or sodium be added to this tincture, the solution loses its 
styptic taste, does not affect the teeth, and is not incompatible with 
solutions containing tannin. 

sulphates. 
Ferrous Sulphate — FeS0 4 — Copperas, Green Vitriol. — Prepared : 

* Experiment. — With the apparatus shown in Fig. 35, hydrogen is gen- 
erated from sulphuric acid and zinc in the Wolff bottle, and dried by passing 
through the U-shaped tube containing calcium chloride. It then passes through 
the porcelain tube containing ferric oxide (sub carbon ate, U. S. P.) and is heated 
to redness in the furnace. After the reduction is completed, the iron should 
not be exposed to the air until cool, or it will ignite spontaneously. 

f Experiment. — Faraday used to show that it is more inflammable than 
gunpowder, by pouring it mixed with gunpowder upon an alcohol flame burn- 
ing on a white dinner-plate. The iron burns with bright scintillations, while 
the gunpowder falls through the flame and is only ignited when the flame dies 
down and reaches the surface of the plate. One part of sulphur, two of 
reduced iron, and three of nitre make an iron gunpowder that burns as quickly 
and more brilliantly than ordinary gunpowder. 



PART I. — INORGANIC CHEMISTRY. 



83 



Fe + H 2 S0 4 = FeS0 4 + H 2 . Soluble, green crystals efflorescing upon 
exposure. A cheap and excellent disinfectant, destroying organic 
matters by abstracting their oxygen. When given in pill form it is 
first exsiccated. . 

Ferric Sulphate — Fe 2 3S0 4 . — Tersulphate is made by adding nitro- 
sulphuric acid (HN0 3 + H 2 S0 4 ) to a solution of the ferrous sulphate, 
thus : — 

6FeSO, + 3 H 2 S0 4 + 2HNO3 = 3Fe 23 S0 4 + N 2 2 + 4 H 2 0. 

Its officinal solution is the liq. ferri tersulphalis. Liq.ferri sub- 
sulphatis, U. S. P., Monsel's Solution, is prepared similarly to the 
above, using only half the quantity of sulphuric acid. 

Fig. 36. 




A Dialyser. 
HYDRATES. 

Ferrous Hydrate — Fe2HO — is precipitated on mixing solutions 
of a hydrate and a ferrous salt, as — 

FeS0 4 + 2NaHO = Na 2 S0 4 + Fe2HO. 

A green precipitate, which soon oxidizes and becomes brown. 

Ferric Hydrate — Fe 2 6HO. — A brownish-red, gelatinous mass, 
precipitated by soluble hydrates from ferric solutions, e.g. ; — 

Fe 2 Cl 6 + 6NH 4 HO = 6NH 4 C1 + Fe 2 6HO. 

This is the favorite antidote for arsenic, for which purpose it must 
be freshly prepared and given in large doses. Ferric hydrate dissolves 
freely in a solution of ferric chloride, forming a dark red liquid of a 
styptic taste. 

If this liquid be put in a dialyser (Fig. 36), a vessel with a bottom 
of parchment or animal membrane, and suspended in water, the 



84 ESSENTIALS OF CHEMISTRY. 

chloride passes out through the membrane into the water. When 
barely enough ferric chloride remains within the dialyser to hold the fer- 
ric hydrate in solution and the styptic taste has disappeared, the liquid 
is removed and sold under the name of " Dialysed Iron." 

Ferric Nitrate — Fe 2 6N0 3 . 

Made : Fe 2 6HO + 6HN0 3 = 6H 2 + Fe 2 6N0 3 . 

Liq.ferri nitralis, U. S. P., is a reddish acid liquid. Used as an 
astringent, especially in dysentery. 

Ferrous Iodide — Fel 2 . — Prepared: Fe + I 2 = Fel 2 . 

Sometimes given in pill, but better with syrup, which acts as a pre- 
servative as well as a vehicle. 

Ferrous Carbonate — FeC0 3 — is obtained by adding a soluble 
(alkaline) carbonate to a ferrous salt, thus : — 

FeS0 4 + K 2 C0 3 = K 2 S0 4 + FeCO,. 

It is insoluble in pure water, but slightly soluble in water containing 
carbonic acid, as in chalybeate springs. On exposure to the air it 
turns red from formation of ferric hydrate ; so it is preserved by mix- 
ing with sugar and honey, as in the ferri carb onas saccharatus, U. S. P. 

Ferrous Sulphide — FeS — occurs native, but may be made by heat- 
ing together iron filings and flowers of sulphur. Used in the prepara- 
tion of H 2 S. 

Scale Compounds of Iron. — These are ferric salts, mostly with 
organic acids. They do not crystallize readily, but are sold as thin 
scales. Made by evaporating their solutions to a syrupy consistence, 
poured upon plates, and when dry peeled off in scales. Often other 
bases, as potassium or ammonium, together with alkaloids, as quinine 
and strychnine, are incorporated in the compound. 

The following are officinal : Ferri citras, ferri et ammonii citras, 
ferri et quinice citras, ferri et strychnia citras, ferri et ammonii tar- 
tras, ferri et potassii tartras, and ferri pyrophosphas. 

Physiological. — Iron is a normal constituent of the body, especially 
the blood corpuscles, where it performs an important function, as is 
shown by the great increase of blood corpuscles and of bodily vigor 
attending its administration. Many of its salts, especially the ferric 
salts of the mineral acids, are astringent and hemostatic. Iron is 
eliminated by various organs, but is mainly discharged by the bowels 
as sulphide blackening the fasces. 



PART I. — INORGANIC CHEMISTRY. 85 

Tests for Iron. — Ferrous salts are usually green ; with NH 4 HS they 
give a black precipitate of FeS. 

Ferric Salts are usually red ; they give a black precipitate with 
NH 4 HS ; a black precipitate with tannic acid ; and a blood-red with 
sulphocyanate of potassium. 

COBALT. — Its chief ore is a compound with arsenic, sold under 
the name of , cobalt or fly stone, for poisoning flies. Its salts are used 
in preparing sympathetic ink, for when free from moisture they are 
deep blue, but almost colorless when moist. Writing done with a 
dilute solution of chloride of cobalt is invisible until warmed, when 
it becomes blue, the color disappearing when the paper is cooled or 
moistened. 

Test for Cobalt. — It imparts a deep blue color to a bead of glass or 
borax melted in the blow-pipe flame. 

NICKEL. — This is a hard, grayish-white metal that does not tarnish 
in the air. Used to electro-plate instruments made of metals more 
prone to corrode, and to make cheap coin. Mixed with brass, it forms 
German silver. 



XI. The Copper Group. 

Copper {Cupruni), Cu 63.4 

Mercury (Hydrargyrum), . . Hg 200 

Each of these elements is univalent and bivalent, forming two classes 
of compounds, " ous" and "ic" At ordinary temperatures they are 
acted upon but slowly by the non-oxidizing acids, as H 2 S0 4 and HO; 
but HNO3 attacks them vigorously. 

COPPER is usually found combined with sulphur, etc., but often in 
the metallic state, especially on the southern shores of Lake Superior. 
Being found free, it was among the first metals wrought by man, so 
the bronze preceded the iron age. Copper is a red malleable metal; 
an excellent conductor of electricity. 

Cupric Sulphate — CuS0 4 — Blue Vitriol, Blue Stone. — Obtained 
as an incidental product from silver refineries, copper mines, etc. ; 
made experimentally by heating copper with strong H 2 S0 4 . Forms 
beautiful blue crystals, soluble in water, but insoluble in alcohol. If 
the crystals be heated they lose their water of crystallization and form 



86 ESSENTIALS OF CHEMISTRY. 

a white powder, which becomes blue again upon the addition of water. 
Hence, used as a test for water in alcohol. Like other salts in which 
the acidulous radical predominates, cupric sulphate is astringent and 
coagulates albumen. A prompt emetic, but not used as much as 
ZnS0 4 , because if, by chance, it be not all ejected from the stomach, 
a gastro-enteritis is liable to be set up. 

Cupric Hydrate — Cu2HO — is formed as a bluish-white precipitate 
whenever a soluble copper salt is treated with a soluble hydrate, thus : 

CuS0 4 + 2KHO =rK 2 S0 4 + Cu2H0. 

When heated, even under water, it decomposes — 

C112HO = CuO + H 2 0. 

Cupric Oxide — CuO — Black Oxide. — Prepared by heating copper 
turnings in air. It gives up its oxygen easily, hence used as an oxid- 
izer in organic analysis. 

Cuprous Oxide — Cu 2 — Stiboxide. — Made by boiling the cupric 
oxide with an oxidizable substance, as glucose (copper tests for glu- 
cose), which is oxidized at the expense of the oxygen of the cupric 
oxide. The precipitate is first yellow (hydrate), but soon becomes a 
bright red (oxide). 

Cupric Sub acetate or Oxyacetate — sometimes called verdigris 
(green-gray) — is made industrially by exposing plates of copper to the 
acetic fumes of grape husks, etc. It is apt to be formed whenever 
fruits containing acetic acid are placed in copper vessels. 

Tests. — 1. Plating Test. Dip into the suspected solution a more 
electro-positive metal, as iron, and a plating of metallic copper will 
be deposited on the iron, an equivalent proportion of which takes 
the place of the copper in the solution. 

2. Sulphur Test. Add H 2 S or NH 4 HS, and if copper be present a 
black precipitate (CuS) will be formed. 

3. Ammonia Test. Add ammonia, and if copper be present a deep 
blue ammonio-salt of copper- will be formed. 

4. Arsenic Test. To the ammonio-salt, described above, add an 
aqueous solution of As 2 3 , and a green precipitate of arsenite of cop- 
per (Paris green) will be thrown down. 

5. Glucose Test Add KHO, (CuS0 4 + 2KHO = K 2 S0 4 + C112HOJ 
and boil (Cu2HO == CuO + H 2 0), with a little glucose, and a yellow- 
ish-red precipitate (Cu 2 0) indicates copper. 



PART I. — INORGANIC CHEMISTRY. 



87 



It will be seen from the last two reactions, above described, that a 
substance acted upon characteristically by a reagent is as good a test 
for the reagent as the reagent is for it — i. e., arsenic and glucose, being 
acted upon characteristically by copper, are as good tests for copper 
as copper is for them. 

Physiological. — Canned fruits, pickles, etc., that have been colored 
green with copper, and food, especially if acid, that has been cooked 
or kept in copper vessels, are apt to produce an acute gastro-enteritis. 
Chronic copper poisoning, so called, is perhaps always due to 
other substances, as lead or arsenic, and should be treated accord- 
ingly. 

Antidotes for acute copper poisoning : Encourage vomiting and give 
albumen (white of egg), which combines with the copper salt to form 
an insoluble albuminate ; or iron filings, which will precipitate the 
copper in metallic state. 




MERCURY is the only metal liquid at ordinary temperatures, and 
resembles silver in appearance, hence the names hydrargyrum (water 
silver) and quicksilver (fluid silver). It is 
so heavy (specific gravity 13.56) that iron 
and % stone float upon it as corks on water. 
(Fig. 37 represents a marble and a ball of 
iron floating on mercury.) It does not tar- 
nish in the air unless contaminated with 
baser metals ; dissolves all metals, except 
iron, to form amalgams. 

Uses. — Metallic mercury is used extensively in the refining of silver 
and gold, in thermometers and other instruments, with tin in silvering 
mirrors, and in many other branches of the arts. Metallic mercury,, 
rubbed up with various excipients until globules cease to be visible, 
forms several officinal preparations. Rubbed with chalk it forms 
" gray powder," hydrargyrum cum creta ; with confection of roses and 
licorice powder it forms ''blue pill," fl Hula hydrargyri ; and with lard 
and suet it forms " mercurial ointment," unguentum hydrargyri. The 
therapeutic activity of these preparations is not due to the metallic 
mercury they contain, but to small quantities of mercurous oxide 
formed by the oxidation of the finely divided metal. So their strength 
varies with the thoroughness of the rubbing, the extent of the expo- 
sure, and the age of the preparation. 



55 ESSENTIALS OF CHEMISTRY. 

Mercurous Iodide — Hgl — Proto-iodide, Green Iodide, Hydrar- 
gyri Iodidum Viride, U. S. P. — Made by rubbing together chemical 
equivalents of mercury (200) and iodine (127) until they combine and 
form a green mass. 

Mercuric Iodide — Hgl 2 — Biniodide, Red Iodide, Hydrargyri 
Iodidum Rubrum. — Made like the above, except that two equivalents 
of iodine (twice 127) are employed. 

Both the iodides, being insoluble, may be precipitated by adding a 
solution of KI to a solution of mercurous salt for the one and a mer- 
curic for the other, thus : — 

HgN0 3 + KI = Hgl + KN0 3 and 
Hg2N0 3 + 2KI = Hgl 2 + 2KNO3. 

The mercuric iodide is dissolved by excess of either the Hg2N0 3 or 
the KI. In precipitating, mercuric iodide is first yellow, but rapidly 
becomes red. If some of the dry red powder be placed on a sheet of 
paper and warmed over a lamp, it changes back to yellow, but on 
shaking or rubbing the red is restored. These changes in color are 
due to changes in crystalline structure. 

Mercurous Nitrate — HgN0 3 — is formed when mercury is treated 
with cold dilute nitric acid. 

Mercuric Nitrate — Hg2N0 3 . — Acid nitrate of mercury is formed 
if the mercury be boiled with strong nitric acid. Like all nitrates, both 
of the above are soluble. It enters into the liq. hydrargyri nitratis, 
U. S. P., and "citrine ointment," ung. hydrargyri nitratis, U. S. P. 

Mercurous Sulphate — Hg 2 S0 4 — is made by digesting sulphuric 
acid with excess of mercury. 

Mercuric Sulphate — HgS0 4 — is made by heating mercury with 
excess of sulphuric acid. A white, crystalline salt, used in some 
forms of galvanic batteries. When diluted with water it decomposes 
into an acid salt, which remains in. solution, and a yellow precipitate 
of oxy sulphate, HgS0 4 .2HgO, called " turpeth mineral," hydrargyri 
sub sulphas flavus, U. S. P. 

Mercurous Chloride — HgCl — Calomel, mild chloride, Hydrar- 
gyri Chloridum Mite, U. S. P. — is made by heating mercurous sul- 
phate with sodium chloride (Hg 2 S0 4 + 2NaCl = Na 2 S0 4 + 2HgCl),' 
when the mercurous chloride sublimes and is condensed in a cool 
receiver. 



PART I. — INORGANIC CHEMISTRY. 89 

Calomel is a white, insoluble powder. Exposed to light it is slowly 
decomposed (2HgCl = Hg + HgCL). With aqua regia, and more 
slowly with other soluble chlorides, it is converted into mercuric chlo- 
ride. Calomel probably passes through the stomach unaltered, but is 
converted into the mercurous oxide by the alkaline fluids in the small 
intestine. 

Mercuric Chloride — HgCL — Bichloride of Mercury, Corrosive 
Subli?nate — is prepared by sublimation from a mixture of mercuric 
sulphate and sodium chloride, thus : — 

HgS0 4 + 2NaCl = Na 2 S0 4 + HgCl 2 . 

It is crystalline and soluble, with a disagreeable styptic taste, and is 
very poisonous ; much used in antiseptic surgery. 

Mercuric Ammonium Chloride — Ammoniated Mercury, White 
Precipitate, U. S. P. — Formed by adding ammonia to a solution of 
mercuric chloride ; mostly used in ointment. It is a double salt of 
mercury and NH 2 , a derivative of ammonium. Its composition is that 
of NH4CI, in which two atoms of H are displaced by one of Hg, 
forming NH 2 HgCl. The ammonio- sulphate of copper previously 
described has an analogous composition. 

Mercurous Oxide — Hg 2 0— Black Oxide of Mercury — is made by 
treating a mercurous salt with a soluble hydrate, as — 

2HgCl + 2KHO = Hg 2 + 2KCI + H 2 0. 

It is seldom used in medicine. 

Mercuric Oxide — HgO — Red or Yellow Oxide. — When prepared 
by decomposing mercuric nitrate by heat, it is crystalline and of a red 
color (Jiydrargyri oxidum rubrum, U. S. P.) ; but when made by pre- 
cipitating a mercuric solution with a hydrate, 

HgCl 2 + 2KHO = HgO + 2KCI + H 2 0, 

it is an amorphous yellow powder {Jiydrargyri oxidum flavum, U. S. P.). 
The yellow variety, being amorphous and more finely divided, is less 
gritty and has greater therapeutic activity. 

Oleate of Mercury is made by warming the yellow oxide with 
oleic acid. A liquid or semi-solid. Applied to the skin it is rapidly 
absorbed. 

Mercurous Sulphide — Hg 2 S — is an unstable compound, which 
7 



9<D ESSENTIALS OF CHEMISTRY. 

falls as a black precipitate when a mercurous solution is treated with 
a soluble sulphide. 

Mercuric Sulphide — HgS — falls as a black precipitate when a 
mercuric solution is treated with a soluble sulphide. It is found in 
nature in crystalline masses called cinnabar. By certain processes 
it may be obtained as a deep-red crystalline powder, called ver- 
milion. 

Tests. — These consist in adding to the suspected liquid solutions of 
salts containing radicals capable of uniting with mercury and forming 
precipitates of the foregoing insoluble compounds. But the galvanic 
test is perhaps the best for clinical purposes. On a gold or copper 
coin put a drop of the suspected solution acidulated with HO, and 
with a piece of baser metal, as a knife blade, touch the coin through 
the drop of fluid. Mercury, if present, will be deposited on the coin 
in a silvery film. 

Physiological. — Acute poisoning occurs from swallowing a single 
large dose of some of the mercuric compounds, especially corrosive 
sublimate. The minimum fatal dose of corrosive sublimate is three 
grains ; of white precipitate and turpeth mineral forty grains. Children 
tolerate mercury much better in proportion to their age than adults. 
The symptoms are those of severe gastro-enteric irritation. Giye 
albumin, with which it forms an insoluble compound. Iron filings 
also act as a chemical antidote by decomposing the salt, taking 
the acidulous radical and depositing the mercury in the metallic 
state. 

Chronic poisoning is often called, from its most prominent symptom, 
salivation or fttyalism. It usually occurs from small, but often repeated 
doses of the mercurous preparations, as blue pill, calomel, etc. One 
of the first symptoms is a delicate red line along the margin of the 
gums, then comes a metallic taste, abdominal pains, nausea, vomiting, 
dysenteric diarrhoea, profuse flow of saliva, fetid breath, fever, emacia- 
tion, and paralysis. Sphacelation of the mouth and lips sometimes 
occurs. The treatment is to stop the ingestion of poison, and give 
some astringent, as tannin. 



PART I. — INORGANIC CHEMISTRY. 9I 

XII. The Silver Group. 

Silver (Argentum), Ag 10S 

Gold (Aurum), Au 197 

Platinum, Pt 1944 

These are heavy, bright metals, not easily corroded, rare and very 
valuable. Silver is univalent ; gold, trivalent ; and platinum, quadri- 
valent. 

SILVER occurs free, but often as a sulphide associated with lead in 
galena. A white, malleable, ductile metal, capable of a high polish ; 
best known conductor of electricity ; dissolved readily by nitric, but 
not by hydrochloric or sulphuric acid, except by the aid of heat ; does 
not tarnish in air unless ozone or H 2 S be present. 

Used to plate mirrors and articles made of the more corrodible 
metals ; alloyed with copper as coin ; for tubes, sutures, etc., in sur- 
gery, for it does not corrode and irritate the tissues. 

Silver Nitrate — AgN0 3 — Argenti Nitras , U. S. P., Lunar Caustic. 
Made by the action of nitric acid on silver. If coin silver be used, 
the solution is blue, from the presence of copper. Silver nitrate is a 
crystalline salt, very soluble. Its taste is acrid, and in large doses it 
acts as a corrosive poison, destroying the tissues by coagulating their 
albumin. For use as a cautery it is fused and moulded into sticks. 

Silver Oxide — Ag 2 — is precipitated as a brown powder on treat- 
ing a solution of silver nitrate with caustic potash or soda (2AgN0 3 + 
2KHO = 2KNO3 + Ag 2 + H 2 0). Slightly soluble in water. The 
other salts of silver are insoluble, and made by precipitating a solu- 
tion of silver nitrate with a solution containing the appropriate radical. 

Silver Cyanide — AgCN. 

AgN0 3 + KCN = AgCN + KN0 3 . 

White precipitate, soluble in ammonium hydrate. 

Silver Chloride — AgCl * 

A gN0 3 + NaCl = AgCl + NaN0 3 . 

* There are three insoluble chlorides, viz., PbCl 2 , HgCl, and AgCl. They 
may be distinguished by ammonia, which dissolves AgCl ; blackens HgCl, and 
has no effect on PbCL. 



92 ESSENTIALS OF CHEMISTRY. 

White precipitate ; insoluble in nitric acid, but freely soluble in 
ammonium hydrate. 

Silver Bromide — AgBr. 

AgN0 3 + KBr == AgBr + KN0 3 . 

Yellowish- white precipitate ; slightly soluble in ammonium hydrate. 

Silver Iodide — Agl. 

AgN0 3 + KI = Agl + KN0 3 . 

Yellow precipitate ; insoluble in ammonium hydrate. 

Effects of Light. — Light decomposes salts of silver, especially if 
organic matter be present, depositing metallic silver in a fine, black 
powder, hence their uses in photography, and in making indelible 
inks, hair dyes, etc. The black stain of silver on the hands or clothes 
may be removed by potassium cyanide or by applying tincture of 
iodine and washing in ammonia-water. When persons have taken 
silver salts for a long time, it sometimes occurs that the tissues, 
especially the skin, are permanently darkened. This is due to the 
decomposition of the silver salt under the influence of organic matter 
and. light. 

Poisoning occurs mostly from swallowing the nitrate, which is the 
only soluble silver salt. It is a severe corrosive poison, destroying 
the tissues by coagulating their albumin. Its best antidote is a 
soluble chloride, as common salt, which forms the insoluble silver 
chloride. Albumin is also a good antidote. 

GOLD occurs widely, but sparingly distributed ; always free, mixed 
with sand and quartz, from which it is separated by agitation with 
water or by dissolving it out with mercury. It is a soft, bright, yellow 
metal ; so malleable that it may be beaten into sheets (gold-leaf) less 
than one two-hundred-thousandth of an inch in thickness. These 
transmit green light. For coinage and general use gold is usually 
hardened by the addition of copper or silver, the amount of which is 
indicated by the term carat fine. Thus, pure gold is twenty-four 
carat, and eighteen, sixteen, and twelve carat signify so many twenty- 
fourths of pure gold. 

Gold does not tarnish in the air ; is unaffected by any single acid, 
but nitro-muriatic acid (aqua regia) easily dissolves it, forming auric 



PART I. — INORGANIC CHEMISTRY. 93 

chloride, AuCl 3l a caustic salt, which is sometimes given as a nerve 
tonic and aphrodisiac. Dose, one-twentieth to one-tenth of a grain. 

PLATINUM, occurs free, associated with the allied metals, palla- 
dium, rhodium, ruthinium and iridium. Owing to its scarcity it is 
almost as costly as gold. Resembles silver in appearance ; can be 
melted only with very great difficulty, and very few substances cor- 
rode it ; hence it is used to make vessels that are to be exposed to 
very high heat or to contain corrosive chemicals. Platinum wire is 
also used in flame testing. 

Platinum readily dissolves in nitro-muriatic acid, forming filafaiic 
chloride, PtCl 4 , a valuable reagent for potassium, ammonium and 
alkaloids. 

In the table of the elements are given the names, symbols and 
atomic weights of many substances that are as yet of little or no 
medical interest, and have therefore not received special description. 
They are rare elements, widely distributed but in minute quantities. 
Some of them are of considerable scientific interest. Molybdenum, 
as ammonium molybdate, forms a valuable test-reagent for phos- 
phoric acid. Osmium, as osmic acid, Os0 4 , is used in microscopy. 



94 



ESSENTIALS OF CHEMISTRY. 



U 

H 

O 



O 



o 
o 



< w 
o ^ 

~* > 
pq 



S o 

W 
X 
H 



g 

s 

W 
H 
W 
fi 

o 

H 

I 

W 

CQ 
< 



PC 
X 

•d 


T3 

•a 

(L) 


o 

c 

> ^ 'I" 


If no precipi- 
te, test origi- 
il solution in 
ime on loop of 
t wire. 

Li, crimson. 
Na, yellow. 
K. violet. 


If neither, 
st orig. sol. for 


c 


« 


^.£^ 


5§<SPh 2£ 




ft 






O 




X 

<* 


o4 


■a* 


fc 














_r 


£E 


u 

> 






u 

<* 


s& 


|g 


. — < * 


"o c« 


X 


CO 


<u .2 rt 


^5s 


OT(J 


*d 

C3 


X 


a; rt > N . 


. 1 


« 


S 








rt 




'5* 
*o 

V 

u 




Z2 3 

o-- 
U 




Q* 






o 

c 


4 


5 - 11 s 


> 





U> 
CO 


*E 







•AvojpA" '^p-qq 



-3 


£•3 


dd 


1) 




o 








c 










§!? 




o 


3 
O 


4J"5" 


H-Clh 




w c 


n 


S3 3 *j 


^^ 




1 


<(fi 


CO 


CO<(^( 






£ 


* ->pm 






o~ 
















>> 


3 
U 


P3 3 








'aw 


-d 


U^ 


TD* 3 ^X 






<< 


U 


~ 


UUffiP- 


pq 




o 



^1? 

'S -Si rt -r: w 3.£5_ 

■sag a . M ^ S ^ > 

t-H a) *^ rt cl:3 

p,rt S 



PART I. — INORGANIC CHEMISTRY. 



95 



fa 
fa 

o> 

2 ^ 

H Q ^ 

^ Z >* 

"^ fa J 

>* £ £ ° 

rV. ^ S ■"! 



< S O 



Pfi i 



55 £ ? 3 

K fa ^ HH 

Q jwK 

: W X p 
<! fa 



. w 



fa 

u w o ^ 

fa fa H fa 

,1 p ^ « 

^ r? A 3 

~ fa Q tf 



fa 
fa 
fa 
< 



fa 
fa 
fa 
fa 
fa 

H £ 

55 5 



O 



co <1 



fa 



& - H 
H fa 



CO 



& o s 

J H ^ 

5^ fa 

6 * ><* 

<< fa fa 

j < 

fa < - 



fa « >7 

•-I fa s 
u 
«! 
u 



H ^ 



CO w 

fa fa 



O O ' 



fa 



fa W 

fa £ fa 

So.o 
S*£fa 

* !Z J Q 
fa ^ ^ i> 

S o < ^ 

fa ^ 

H co ^ 

I 00 

a P 

m 
< 



fa fa! 

fa Q 
Q fa" 

^ CJ 

w < 
H co 

H 

CJ 
fa 

fa 
fa 
fa 



El> 



2 o 



^" ^ (L) ^ 
^ OJ <U uo 



•7 • rt 

•X; <u . »-i 

IPs sulk 



^ </> « c «T3 

a 2 aj o ££ 

J3 °j£ rt ^ 3 

fa MOCJ*<co 




;UUUOcoH fa ~fa 




o <y -C _• x -o c c -d <u be 

-^coyfiuScOfi 

„< o 5 <I *■* rt u, rt 2.w > 









^E 







<U <UCO C c bJO ™ 13 13 ^TS'tf 
.— "J fa >-v ^ > Jj O r* *+ r* TJ «i 



^O^ 



>OC0^2C5X!CO 



rt o *o « U ,^j v 



L"iS'iS: 



S.5 S 

fax: o 
cocoU 



9 6 



ESSENTIALS OF CHEMISTRY. 



& 


c 




H 






H 


43 




<| 







> 






?*■ 


a 




fc 


£ 


V 


HH 


c 




ro 


^ 


C 


H 


m 


.V 




J 


rt 


< 


en 


TJ 




,2 


In 

c 
c 


O 





£ 


> 


3 




P5 


H 





a 




■y; 


hJ 


en 






3 


n- 
U 


pq 



4) 

a 


J 


cr 


43 


U 




J3 

5 


2; 


n 


a 








* 


■x. 


i-T 


n 


V 


• * 









> 


—. 


JQ 


H 




a 


i—i 





1-1 


M 






>i 


pq 


hi) 




P 


C 


X 


J 


>» 




O 


ft 


en 


1/3 


Cm 


fr T 


W 


rt 


Cfl 


3 




C 


u 


H 


>> -O 


1 


X) 


a 


W 


T3 







> 


co 


< 


u 




H 


a 

E 
5 





•31E.H-IBJL 


</: en (/} (/) entn en en 

coco^hhhhc/}cocococococo<n. hhcocoh-ih-i^<n. coi-icocn-cococo 


•33iqd{n§ 


en en en en en en 
1 •— 'C/21—i!— 11— IC/2COC/2COI— ««>-CCo— •— 'C/DC/3<^- »-COCOCOi-<COcn.h-ii-ic/2 


•gpiqdms 


1 •— iCC"— 'C/3>— ii— ioqi— 11— 1— ! 1 — 1 1— • 1 — 1 1 — 1 «r— »— 1 f— 1 1— 1 »— c 1— 1 c/3 •— • C/3 1 — • •— ■ CO •— • 


•s^qdrng 


en v> -.a 


•siBqdsoqj 


HCQHHHHHHHHHHHHHHHHHcCOMCflHMHH 


•apixQ 


en 

i Me ..h^^^l-ICOt-<HHt-l(-ll-l»HI-ll-lh-IH-IHHi-ll-ICO"-ltOl-ll-IC/5l-l 


•3JB|^XQ 


1 >-ic/3(73^^i^^c/2m^C072cn.i-ii-ii-ii-ii-ii-h<n.c/3hhc/3C/3»^i-ii-h 


-a?Bi?i£[ 


cococn-cococococococococo^-cocococococococococococococo 


•spipoj 


<^-CO>-<CO>--iCOCOCOCO # {y}COHHC/}{7}COi-HHHCOC/2COi-<COCOCOCOCO 


•ai^jpXH 


►-• CO »-* CO •-• •-* CO «-l HH H-l »-l HH l-l Cfl HH HH H-l <N- t-1 H-l (/) «- (fl)«-l ** 03 »- 


•spiuBX^ 


^co^co^^co-.h-, m ^hh ^to-~~co,-.c«-*-eo*H 


•3jeiuoaq3 


h-i CO — "-< — cn. c/2 h* <n- c/3 c73 ^- =-• h-i y; CO CO h-i hm cn. 73 »-i CO »-h 1-1 "-• CO 


•35^1513 


in<fi<^-wui&&wwwww^-ui<fi^<>'~w^''j)*in<>-'^'*in 


apuojq^ 


COCOCOCOCOCOCOCOCOCOCOCOCOCOCOCOCO^COCOCOh-iCOCOCOcOCO 


, 'aj^uoqj^f) 


HHC0CN.I-IH-II-II-II-II-II-ICN.I-KN.H-. l-IH-IH-fH-IH-.O.COH-lCOCN. O- HH 1-1 


•ajmasay 


HHCOH-IH-ICN. (N.HH(N.H-.HHH-IHHCN.HHH-l<N.H-IH-HH<N.COH-lCOHHHHHHCN. 


•3;Biu3say 


mWhhm>.h- 1 mmmmmhhhmhhmCOh^^mhh- 


•a^aoy 


wwwwwtnin'Awtnww^wwwmwu^^-inwwwu^inin 


















Aluminium, 
Ammonium, 
Antynony, . 
Barium, . . 
Bismuth, . 
Cadmium, . 
Calcium, . 
Chromium, 
Cobalt, . . 
Copper, . . 
Ferric, . . 
Ferrous, . . 
Gold, . . . 
Lead, . . . 
Magnesium, 
Manganese, 
Mercuric, . 
Mercurous, 
Nickel, . . 
Platinum, . 
Potassium, 
Silver, . . . 
Sodium, . . 
Stannic, . . 
Stannous, . 
Strontium, . 
Zinc, . . . 



PART II.— ORGANIC CHEMISTRY. 



Formerly organic chemistry was defined as the chemistry of the 
compounds produced only by organized life. Gradually this defini- 
tion has been abandoned, for with the increase of chemical knowledge 
many substances identical with the animal and vegetable products 
have of late years been made in the laboratory without the aid of the 
vital force, and probably, if their chemical constitution were fully 
understood, all animal and vegetable products could be duplicated arti- 
ficially. However, chemistry has not, and probably never will, produce 
an organized body, i. e. y one having an anatomical, cellular structure. 

It is a noticeable fact that every organic compound contains carbon. 
Hence, organic chemistry is now defined to be "the chemistry of the 
carbon compounds," and the following pages may be considered a 
resumption of the study of that element. 

Though carbon forms compounds of infinite number and extreme 
complexity, it is with the aid of a very few other elements, viz. : hydro- 
gen, oxygen, nitrogen, and occasionally sulphur, phosphorus and 
iron — sometimes others ; but the larger number of even the artificial 
compounds contain only the above-named elements. This is due to 
the fact that the carbon atoms possess, in the highest degree, the power 
of cotnbining with each other and interchanging valences, forming 
groups or chains around which the other elements are arranged. But 
for this power carbon could form only one saturated compound with 
hydrogen, CH 4 . Carbon being quadrivalent, the compounds C 2 H 6 
and C 3 H 8 would be unsaturated. Experiment, however, proves that 
they are saturated compounds. The explanation is that the carbon 
atoms combine with each other, mutually neutralizing one or more 
valences, thus: — 

H H H II H H 

H— C— H ; H— C— C— H ; H— C— C— C— H. 

I II III 

H H H H H H 

97 



98 ESSENTIALS OF CHEMISTRY. 

It will be observed that these formulae have a common difference 
of CH 2 . They are said to form a homologous series. When the car- 
bon remains the same but the hydrogen differs by H 2 , the series is 
said to be isologous. 

In the following examples each vertical column represents a ho- 
mologous, each horizontal line an isologous series : — 



C H 4 


C H 2 


C 


C 2 H 6 


C 2 H 4 


C 2 H 2 


C 3 H 8 


C 3 H 6 


C 3 H 4 


C 4 H 10 


C 4 H 8 


C 4 H 6 


C 5 H 12 


C 5 H 10 


C 5 H 8 


etc. 


etc. 


etc. 



Without this arrangement in series, it would be impossible to 
remember the composition of organic substances. 

In systematic works on organic chemistry, these series form the 
basis of classification ; but as this necessitates mentioning thousands 
of bodies of no medical interest, it would be impracticable in a work 
like this. We shall therefore adopt the following : — 

Hydrocarbons and their deriva- Organic acids. 

tives. Carbohydrates (sugars and 

Alcohols. starches). 

Ethers (including oils and fats). Glucosides. 

A Idehydes. A mmonium su bstitu lions. 

Natural alkaloids. 

Hydrocarbons are compounds of carbon with hydrogen. Of 
these CH 4 * is the type from which all the other members of this class 
may be regarded as derived in isologous or homologous series. 
Petroleum is a mixture of the homologous derivatives from the first 
(CH 4 ) to about the sixteenth (C 16 H 34 ). These are separated by dis- 
tilling the crude oil. Those having the smallest molecules, being 



* CH 4 , nietkane, ?narsh gas or light carbwetted hydrogen, is a constituent of 
coal (illuminating) gas, and is also formed by the decomposition of vegetable 
matter under water, as in marshes. It occurs sometimes in coal mines (fire 
damp) where, mixed with air, it causes fearful explosions. Made in laboratory by 
heating a mixture of four parts each of sodium acetate and sodium hydrate with 
six parts of lime in powder. It is colorless, almost odorless, and not poisonous. 



PART II.— ORGANIC CHEMISTRY. 99 

lightest, pass over first, forming naphtha, benzine, etc.* As the heat 
is increased the medium-weight compounds come over next, forming 
kerosene. The residuum consists of the heaviest carbohydrides, which 
can be distilled only by high heat, forming lubricating oil, vaseline, 
paraffine, etc. All the lighter products are liable to give off vapors 
which, mixing with air, are explosive. In most States it is illegal to 
sell kerosene which gives off an inflammable vapor (" flashes ") below 
100 F. 

The Turpene series begins with tritone, C 3 H 2 , but it is the eighth 
member, Ci H 16 , that is of medical interest, for this represents the 
composition of most of the volatile or essential oils. These various 
oils (of lemon, orange, cloves, pepper, lavender, bergamot, etc.), 
though having differences in chemical and physical properties, all 
have the same composition, Ci H 16 . 

Such bodies are said to be isomeric (icog, equal, [ispog, part). 

Volatile oils are found in plants, especially the flowers, of which 
they are usually the odorous essences (hence called also essential oils). 
Obtained by distillation from flowers, etc. Very slightly soluble in 
water {aquce), but quite soluble in alcohol (spiritus). A cologne is an 
alcoholic solution of an assortment of volatile oils. 

Turpentine {oleum terebinthince , U. S. P.) is the most important of 
the volatile oils, and may be taken as a type of the class. It is a thin, 
colorless liquid, a valuable solvent of oils and resins ; absorbs oxygen 
and stores it up as ozone, gaining thereby oxidizing, antiseptic, and 
disinfectant properties. By the action of concentrated sulphuric acid, 
turpentine is changed into terebene (C 10 Hi 6 ), a valuable remedy for 
bronchitis and flatulence. 

On exposure to air the turpenes oxidize with the production of resins 
and camphors. 

Resins are a numerous class, many of which are true acids. Soluble 



* Rhigoline 




boils at 3 2° F., 


used as spray for anaesthesia. 


Gasoline 




a 


1 19 F., 


" for making " air gas." 


Naphtha 




a 


220° F., 


" " dissolving fats and rubber. 


Benzene 




n 


300 F., 


" " varnishes and paints. 


Kerosene 




a 


350 F., 


" " ordinary lamps. 


Mineral sperm 


oil « 


425 F., 


" " lubricating machinery. 


Lubricating 


oil 


" 


575° F., 


n a a a 


Petrolatum, 


U. 


S. P., 


semi-solid, 


" " ointments. 


Paraffine, 






solid, 


" " candles, etc. 



IOO ESSENTIALS OF CHEMISTRY. 

in alcohol but insoluble in water, except by the intervention of an 
alkali, with which they will unite to form soluble soaps. 

The officinal resin (resina, U. S. P.) is formed by the oxidation of 
turpentine as it exudes from the pine tree. 

Solutions of shellac, mastic, copal and others are used as varnishes. 

In the natural state resins are usually mixed with other substances.* 
Mixed with volatile oils they form oleo-resins and balsams, e.g., 
benzoin, tolu, and balsam of Peru, and with gums, gum-resins, e.g., 
ammoniac, myrrh and asafcetida. 

Camphors. — Common camphor — C 10 H 16 O — obtained from the cam- 
phor laurel, is a white, crystalline, volatile solid of a peculiar pungent 
order ; slightly soluble in water (aqua camphors, U. S. P.), and freely 
soluble in alcohol (tinct. camphorce) and ether. 

Monobromated camphor — C 10 H 15 BrO — used in medicine as a seda- 
tive, is formed by substituting one atom of bromine for one of hydrogen 
in ordinary camphor. 

Menthol is a camphor-like body found in oil of peppermint, and 
possesses the odor of that plant. 

Caoutchouc, or India-rubber, and gutta-percha are inspissated juices 
of certain tropical trees. Caoutchouc is elastic ; gutta-percha is not. 

* Proximate and Ultimate Principles. — Most organic bodies in their 
natural state are mixtures of several different substances. These substances 
that naturally exist, mixed together to form a body, are called its proximate 
principles. The separation of these unaltered is called proxi??iate analysis. 
Different methods must be devised for different substances. For example : 
Take a piece of vegetable tissue containing woody fibre, starch, sugar, resin, 
and volatile oil. The oil is removed by a gentle heat ; the resin is dissolved 
out by alcohol ; the sugar by cold water, and the starch by boiling in water, 
leaving the woody fibre. 

The ultimate principles of a body are the elements (carbon, hydrogen, etc.) 
of which it is composed, and the recognition and measuring of these is iritimate 
analysis. This, while requiring careful manipulation, is simple in principle. 
The body is burned with a full supply of oxygen, converting the carbon into 
C0 2 and the hydrogen into H 2 0. These are collected and weighed, and the 
quantities of carbon and hydrogen in them are calculated. The amount of 
oxygen, if any, is determined by subtracting the sum of the carbon and hy- 
drogen from the weight of the original body. For example : 46 grains of 
alcohol (C, H and O) burned completely makes : — 
&> grains of C0 2 equivalent to 24 grains of C. 
54 grains of H 2 equivalent to 6 grains of H. 
46 grains alcohol, minus 30 grains (24 +6), = 16 grains of O. 

The less common elements, chlorine, nitrogen, sulphur, phosphorus, etc., are 
determined by special methods. 



PART II. — ORGANIC CHEMISTRY. 



Both are hardened (vulcanized) by combining with sulphur. They 
are unaffected by most chemicals and solvents. Chloroform is their 
best solvent. 

Alcohols. — The Alcohol Radicals are a homologous series of uni- 
valent basylous radicals, so called because they are the bases of the 
most important alcohols. Their compounds are numerous, and enter 
largely into the materia medica. In the following table a few of these 
compounds are given : — 



Radicals. 



I Alcohols | 
(Hydrates). 



Oxides, 
Ethers. 



Examples of Com- 
pound Ethers. 



Nitrates. Sulphates. 




Acids. 



Methyl 

Ethyl, 

Propyl, 

Butyl, 

Amyl, 

Hexyl, 



CH 3 
C 2 H 5 
C 3 H 7 
C4H9 
CoH n 
CgH 13 
etc. 



CH 3 HO 
€oH 5 HO 
C 3 H 7 HO 
C 4 H 9 HO 
C 5 H u HO 
C 6 H 13 HO 
etc. 



(CH 3 ) 2 
(CoH 5 ) 2 
(C 3 H 7 ) 2 
(C 4 H 9 ) 2 
(C 5 H n ) 2 
(C 6 H 13 ) 2 
etc. 



CH 3 N0 3 
C0H5NO3 
C 3 H 7 N0 3 
C 4 H 9 N0 3 

C5H11NO, 

C 6 H 13 N0 3 

etc. 



(CH 3 ) 2 S0 4 
(C>H 5 ) 2 S0 4 
(C 3 H 7 ) 2 S0 4 
(C 4 H 9 ) 2 S0 4 
(C 5 H n ) 2 S0 4 
(C 6 H 13 ) 2 S0 4 
etc. 



CH 2 G 2 
CoH 4 2 
QH 6 2 
C 4 H 8 2 
C5H 10 O 2 
C 6 H 12 2 
etc. 



In the formation of these compounds the starting-point is not the 
radicals, but their hydrates, the alcohols. When an alcohol is oxidized 
with a limited supply of oxygen, two atoms of hydrogen are removed 
and no oxygen is added. This forms the aldehyde, thus : — 



Methyl 
Aldehyde. 

CH3HO + O = CH 2 + H 2 0. 



Methyl 
Alcohol. 



If there is a full oxidation, an atom of oxygen takes the place of the 
two atoms of hydrogen removed, and forms the corresponding acid, 
as — 

Methyl Formic 

Alcohol. Acid. 

CH3HO + 2 = CH 2 2 + H 2 0. 

In the formation of aldehydes and acids the radical supplies part 
of the hydrogen removed and loses its identity. As part of the 
hydrogen in an acid forms the positive radical, it is written first ; e.g., 
formic acid is written HCH0 2 , instead of CH 2 2 . The various other 
compounds of these radicals are called ethers ; the oxides being called 
simple ethers, the others compound ethers. They are generally formed 
by treating the appropriate alcohol with the appropriate acid. 

Methylic Alcohol — CH 3 HO — Wood Naphtha, Wood Spirit, 



102 ESSENTIALS OF CHEMISTRY. 

Wood Alcohol, Pyroligneous Spirit, Methyl Hydrate — does not exist 
in nature. Made by the destructive distillation of wood. The com- 
mercial article has a very disagreeable odor and taste from the pres- 
ence of tarry matters, etc. ; but when pure, methylic alcohol resembles 
ordinary alcohol in its properties and physiological action. It is not 
used in medicine, but is extensively employed in the arts as a solvent, 
as in the preparation of varnishes, etc. 

Methylated spirit is ordinary alcohol to which has been added 
one-tenth part of commercial methylic alcohol to render it unfit for 
drinking, and thus relieve it of the heavy tax imposed upon alcoholic 
beverages. 

Ethylic Alcohol — C 2 H 5 HO — Ethyl Hydrate, Spirits of Wine, 

Vinic Alcohol, Alcohol. — Alcohol does not exist in nature, but is pro- 
duced in a number of reactions. Liquids containing it (wines, etc.) 
have been known from the remotest antiquity, and are obtained by 
allowing liquids containing glucose (grape sugar) to ferment. 

Glucose. Alcohol. Carbon Dioxide. 

C 6 H 12 6 = 2C 2 H 5 HO + 2C0 2 . 

The alcohol is then separated by distillation, for, being more vola- 
tile than the water, it passes over first. 

Commercial alcohol always contains water, and when pure or abso- 
lute alcohol is required, the commercial article is mixed with some 
substance which is very avid of water, as quicklime, and then again 
distilled. 

Alcohol is a light, colorless liquid, of a pleasant, pungent odor and 
burning taste. Has a great affinity for water, which probably accounts 
for its preserving animal tissues and coagulating albumin. 

It is largely used in the arts and in pharmacy, principally as a sol- 
vent, but also in the manufacture of various substances, as vinegar, 
chloral, chloroform, iodoform,* ether, etc.; and as a fuel when a hot 
and smokeless flame is needed ; and as a menstruum in the prepa- 
ration of tinctures and spirits. 

Alcoholic solutions of fixed medicinal substances are called tinc- 
tures ; those of volatile principles, spirits. 

Alcohol is employed in various forms and degrees of concentration. 

* Experiment. — To test for alcohol in a solution : Warm; add a few scales 
of iodine, and then caustic potash until the color is discharged. On cooling, 
yellow scales of iodoform are deposited. 



PART II. — ORGANIC CHEMISTRY. I03 

Absolute alcohol is rarely employed. Alcohol fortius, U. S. P., stronger 
alcohol, contains 92 per cent, of alcohol. Alcohol, U. S. P., is the 
ordinary rectified spirit, and contains 85 per cent, of alcohol. Alcohol 
dilutwn, U. S. P., diluted alcohol, is made by mixing water and alco- 
hol, equal parts. 

Spiritus frumenti, U. S. P., whisky, and spiritus vini gallici, U. S. 
P., brandy, are obtained by distillation ; the former from fermented 
grain, and the latter from fermented grape juice. They contain about 
50 per cent, of alcohol. They are colored by the addition of caramel 
(burnt sugar). Their flavor is due to small quantities of other alcohols 
produced in the fermentation, and to certain ethers formed from these 
alcohols, especially as the liquor "ages." 

A large, class of alcoholic beverages are made by fermenting 
various liquids containing sugar or some substance capable of con- 
version into sugar. 

Beer, ale and porter are infusions of malted grain, fermented and 
flavored with hops. They therefore contain the soluble constituents 
of the grain. Their alcoholic strength is about 5 per cent. Wines are 
prepared by allowing grape juice to ferment. The alcoholic strength 
of the different varieties varies from 10 to 25 per cent. Sherry (vinum 
Xericwri) and port (vinum rubrum) are the only ones officinal. Cider 
is the fermented juice of the apple, prepared very much in the same 
way as wine is from grape juice, and contains about 5 per cent, of 
alcohol. It is very prone to acetous fermentation and liable to 
produce colic and diarrhoea. 

Alcohol, when concentrated, abstracts water from the tissues and 
coagulates their albuminoid constituents, and is a poison. In full 
doses (always best with food) it produces a sense of warmth in the 
stomach, general comfort and exhilaration, followed by incoherence 
of ideas and impairment of muscular coordination. Taken habitually, 
in any of its forms, it impairs the mental and moral force of its victim 
and produces in the various organs, especially the liver and kidneys, 
the degenerative changes characteristic of chronic alcoholism. It 
should never be taken in health, but as a medicine it is the most 
valuable of stimulants. In cases of acute poisoning by alcohol, the 
stomach and bladder should be evacuated, and the depression (coma) 
counteracted by strong coffee, the cold douche, and other stimulants. 

Amylic Alcohol — C 5 H n HO — Amyl Hydrate, Fusel Oil.— This is 
a heavy liquid, soluble in alcohol but not in water, hence incorrectly 



104 ESSENTIALS OF CHEMISTRY. 

called an oil. It is produced in the fermentation of grain and pota- 
toes, and is the most deleterious impurity in common whisky before 
it has undergone the refining process. 

It has a penetrating, disagreeable odor, resembling that of mean 
whisky. Although not fragrant itself, its ethers, when dissolved in 
ethylic alcohol, have the taste and odor of various fruits, and are used 
in the preparations of artificial fruit essences.* 

The other alcohols of this series are of no medical interest. 

Glycerylic Alcohol — C3H53HO — Glycerine. — Being made from 
fats in the manufacture of soaps and candles, it has been called 
(Scheele, 1779) the "sweet principle of fats" ; but it has no chemical 
analogy to them, being the hydrate of the trivalent radical glyceryl, 
C3H5, and therefore an alcohol. It is a colorless, odorless, sweet, 
viscid liquid, avid of water, neutral in reaction ; a solvent of a great 
many mineral and organic substances (glycerites), ranking in this 
respect next to alcohol and water. Glycerine is used in medicine 
mainly as a solvent and as a local application. 

Nitroglycerine — C 3 H 5 (N0 3 )3 — is formed by treating glycerine with 
nitric acid. It is an oily liquid and one of the most dangerous of 
explosives. Mixed with fine silica (sand) it is dynamite. 

In medicine nitroglycerine is used as a heart stimulant. 

Phenyl Alcohol — C 6 H 5 HO — Phenol— Carbolic Acid. — This is an 
alcohol, the hydrate of phenyl, C 6 H 5 , a radical of the aromatic series, 
but is called an acid because it combines with bases and forms bodies 
resembling salts (carbolates or phenates). 

Carbolic acid is formed in a number of reactions, but the commercial 
article is obtained exclusively from coal tar. It has a strong, dis- 
agreeable odor ; occurs as white crystals, which melt on the addition 
of a small quantity of water ; reddens by age ; slightly soluble in 
water, but very soluble in glycerine, the solution being soluble in 
water ; stains skin and mucous membranes white by coagulating their 
albumin ; and is a corrosive poison. Albumin is its best antidote. 

Carbolic acid is a powerful antiseptic and disinfectant. Applied 
locally it is astringent, sedative, and even anaesthetic. 

* Experiment. — To a half drachm of fusel oil in a test-tube add some 
sodium or potassium acetate and a few drops of sulphuric acid. Wann the 
mixture, and the acetate of amyl (essence of pear) may be recognized by its 
odor. 



PART II. — ORGANIC CHEMISTRY. I05 

Carbolic acid and sulphuric acid will combine to form sulpho- 
carbolic acid (phenyl bisulphate, C 6 H 5 HS0 4 ). Sodium sulphocarbolate, 
U. S. P., is a soluble salt sometimes used in medicine. 

Resorcin — (C 6 H 4 2HO). — Closely related to phenol, but a stronger 
antiseptic and much less poisonous. It occurs in soluble, colorless, 
odorless crystals of a sweetish taste. It is given as an antizymotic in 
diseases attended with fermentative changes and in the specific fevers. 

Creasote is a complex mixture obtained from wood tar ; closely 
allied to carbolic acid in its properties and uses, but may be readily 
distinguished from it by being insoluble in glycerine. 

One of the constituents of creasote is guiacol, of late used as an 
inhalation in phthisis. 

Mannityl Alcohol — C 6 H 8 6HO — Mannite. — This is the principal 
ingredient in manna, a white, gummy substance exuding from certain 
trees. Mannite is a crystalline substance closely resembling glucose, 
except that it does not undergo the vinous fermentation, and does 
not respond to Trommer's or Fehling's tests. 

Ethers. — The simple ethers (oxides) are the results of dehydrating 
two molecules of alcohol by means of sulphuric acid ; the compound 
ethers are made by treating the appropriate alcohol with the appro- 
' priate acid. 

Ethyl Oxide — (C 2 H 5 )oO — Sulphuric Ether, Ether. — Ether is made 
by distilling a mixture of alcohol and sulphuric acid ; * hence, the 
misnomer, sulphuric ether. 

A small quantity of sulphuric acid is capable of converting a large 
amount of alcohol into ether, for it is unaltered in the reaction ; in 
fact, the process might go on indefinitely but for the acid being so 
diluted with the water derived from the alcohol, as to finally stop the 
reaction. The sulphuric acid is said to act by its mere presence, by 
catalysis ; or, in other words, it acts because it acts, a ready but femi- 
nine way of explaining many otherwise inexplicable chemical and 
physiological phenomena. 



* Experiment. — Into a large test-tube pour alcohol and half as much sul- 
phuric acid; warm and note the odor of the ether evolved. Next adapt a cork 
with delivery tube, and slowly distill the ether into a cool test-tube. By adding 
more alcohol the operation may be repeated again and again. 



Io6 ESSENTIALS OF CHEMISTRY. 

The true rationale is as follows : — 

C 2 H 5 HO + H 2 SO, = C 2 H 5 HS0 4 + H 2 0. 
And then 

C 2 H 5 HS0 4 + C 2 H 5 HO = (C 2 H 5 ) 2 + H 2 SO,. 

Ether is a colorless, very volatile liquid, of a peculiar odor, called 
ethereal. It burns easily, and its vapor, mixed with air or oxygen, 
explodes when ignited ; * so ether should never be used near, espe- 
cially above, a flame. Ether is a valuable solvent, and, as it evapo- 
rates very rapidly, it is used to produce cold.f But its chief use in 
medicine is as an anaesthetic. Being less liable to paralyze the nerve 
centres, it is safer than chloroform. 

Ethyl Chloride — C 2 H 5 C1. — Hydrochloric ether must not be con- 
founded with the so-called chloric ether, which is an alcoholic solution 
of chloroform. 

Ethyl Bromide — C 2 H 5 Br — Hydrobromic Ether. — A valuable 
anaesthetic, but not much used. 

Ethyl Nitrite — C 2 H 5 N0 2 — Nitrous Ether. — If nitric acid be 
treated with copper or starch it loses part of its oxygen, being con- 
verted into nitrous acid (HN0 2 ), which will unite with alcohol, forming 
nitrous ether and water, thus : — 

C 2 H 5 HO + HN0 2 = C 2 H 5 N0 2 + H 2 0. 

Nitrous ether is a yellowish liquid, of an apple-like odor and sweetish 
taste. It is used only diluted with alcohol, forming the spiritus cetheris 
nitrosi, U. S. P., commonly called sweet spirits of nitre. 

Amyl Nitrite — C 5 H n N0 2 . — Made like ethyl nitrite, except that 
amylic alcohol is used. Nitrite of amyl is a volatile, oily liquid, of a 
peculiar odor, resembling that of bananas. It is given by inhalation, 
especially in epilepsy, for which purpose it is put up in glass bulbs 
holding about two drops. These are crushed and inhaled during the 
aura. 

Chloroform — Trie hlorme thane. — Methyl, having only one free 

* Experiment. — Put a drachm of ether in a dish and apply a flame. The 
vapor, mixed with air, explodes ; the rest burns rapidly. 

f Experiment. — Set a test-tube of water in a beaker of ether. Blow air 
briskly through the ether; the water will freeze. 



PART II. — ORGANIC CHEMISTRY. I07 

valence, must give up two atoms of its hydrogen in order to combine 
with three atoms of chlorine, making the formula of chloroform 
CHCI3. This is the most used of all the ethers. Chloroform is made 
by distilling a mixture of chlorinated lime, water, and ordinary alcohol, 
but of late is being made by a patented process from acetone, which, 
being a by-product in certain technical operations, is very cheap. It 
is a colorless, volatile liquid, of a pleasant ethereal odor and sweet 
taste. It is heavier than water, and does not dissolve in it, but is 
soluble in alcohol and ether ; not easily ignited ; a good solvent for 
phosphorus, iodine, India-rubber, and the alkaloids. Chloroform is 
sometimes given by the stomach as a sedative, but most frequently 
administered by inhalation as an anaesthetic, for which purpose it 
should be of undoubted purity. Pure chloroform is not colored by an 
equal volume of pure sulphuric acid, nor should its specific gravity be 
below 1.480. 

If chloroform be taken by the stomach, it being insoluble, is 
absorbed very slowly ; and its principal action is the local irrita- 
tion of the mucous surfaces. Recovery has followed a dose of four 
ounces, and death has been caused by one drachm taken into the 
stomach. The vapor acts more energetically, and seems to owe its 
potency for evil to its paralyzing influence on the nerve centres, 
especially those of the heart. So chloroform vapor should never be 
administered except by a capable physician, and well diluted with 
atmosphere. However, death has occurred from the inhalation of 
moderate quantities of chloroform properly diluted, and at the 
hands of careful physicians, and the autopsy revealed no heart 
lesion. 

There is no chemical antidote for chloroform. When it has been 
swallowed, evacuate the stomach ; when inhaled, lower the head, give 
fresh air, employ artificial respiration, and apply the induced current. 

The poison is usually recognized by its odor. 

Iodoform — CHI 3 . — Made by the action of iodine and potash on 
alcohol ; yellow scales ; insoluble in water, and of a saffron-like odor, 
which is the chief objection to its use. Light decomposes it, giving it 
a violet color. Iodoform is used on ulcers, etc., as an anaesthetic, 
alterative and antiseptic. 

Fixed Oils and Fats. — These are ethers — combinations of glyceryl 
(C3H5) with oleic, stearic, butyric, palmitic, and other fat acids. The 



108 ESSENTIALS OF CHEMISTRY. 

natural fats are mixtures of these. * Those containing mostly oleate 
of glyceryl (olein) are liquid. Warm-blooded animals yield mostly 
solid ; cold-blooded, liquid fats. Drying oils are such as absorb oxygen 
from the air and become resinous, e.g., linseed. Many fats partially 
decompose on exposure, producing free acid, and become rancid. 
The fixed oils are insoluble in water, soluble in alcohol, ether and 
chloroform. 

The compounds of the fatty acids with the metals of the alkalies 
(K, Na, NH 4 , etc.), are soluble and are called soaps. The soaps formed 
with the other metallic radicals are insoluble and usually called plas- 
ters. Lead plaster is officinal. Soaps are made by the saponification 
of a fat with a caustic alkali. For example : — 

Stearine. Sodium Stearate. Glycerine. 

(C 3 H 5 )(C 18 H 32 2 ) 3 + 3 NaHO = 3 NaC 18 H 35 2 + C 3 H 5 (HO) 3 . 

When soap dissolves in cold water, it decomposes into an acid salt 
which makes the soapsuds and a small quantity of free alkali which 
does the cleaning. 

Aldehydes. — An unimportant class. They constitute the first step 
in the oxidation of alcohols into acids, viz., the removal of hydrogen 
(hence the name). Since nothing has taken the place of the hydro- 
gen removed, they are unsaturated and very prone to change, 
especially to take on oxygen and form the acids. 

Ethyl Aldehyde, acetic aldehyde, or simply aldehyde f (C 2 H 4 0), 
is a colorless, volatile, acid liquid of a pungent odor. One of its 
modifications, called paraldehyde, is used as a hypnotic, which unlike 
morphine is followed by no unpleasant effects, except a pungent 
odor to the breath, and, unlike chloral, does not affect the heart. 
Dose, 3ss-3j. 

Chloral. — If chlorine displace three atoms of hydrogen in ethyl 
aldehyde, it forms tri-chlor-aldehyde, or chloral (C 2 HC1 3 0), a colorless, 



* In "lanolin," the fat obtained from sheeps' wool, the fat acids are com- 
bined not with glycerine, but with cholesterine, C 26 H 43 HO, an excrementitious 
principle of animal bodies. It is a very absorbable base for ointments. 

f Experiment. — To a little bichromate and sulphuric acid mixture in a 
test-tube add a little alcohol; or hold a hot glass rod in a beaker containing a 
little ether. The peculiar pungent odor is that of aldehyde. 



PART II. — ORGANIC CHEMISTRY. I09 

heavy liquid. With a molecule of water this forms a white crystalline 
solid, called chloral hydrate, having a pungent but agreeable odor 
and taste. Warmed with an alkali it decomposes, thus : — 

Chloral. Sod. Formate. Chloroform. 

C 2 HC1 3 + NaHO = NaCH0 2 + CHC1 3 . 

Liebreich thought this reaction would occur in the warm alkaline 
blood and the sedative action of chloroform be obtained. Though 
mistaken in this, he found chloral hydrate a valuable hypnotic. The 
chloral habit is difficult to cure. In overdoses chloral is a poison, 
and cases are multiplying as its powers become better known. No 
chemical antidote. Evacuate the stomach, give stimulants, and main- 
tain the respiration and bodily warmth. 

Organic Acids. — These are regarded by chemists as the natural 
results of the oxidation of alcohols. But as most of them were dis- 
covered before their relation to the alcohols was known, their names 
often have no connection with those of the alcohols. We take up 
only the most important. 

Acetic Acid. — HC 2 H 3 2 . — This is the acid of vinegar. Formed in 
a great many reactions, but made mainly by the destructive distilla- 
tion of wood, or by the oxidation of ordinary alcohol. If wine, cider, 
or other alcoholic liquors be exposed to the air, a fungus (inycoderma 
aceti} forms on the surface and acts as an oxygen carrier, and the 
alcohol is converted into acetic acid, thus : — 

C 2 H 5 HO + 2 = HC 2 H 3 2 + H 2 0. 

A more rapid process is to pass the alcohol through barrels filled 
with beech shavings. 

Acetic acid is a colorless liquid, of a pungent, sour taste and smell. 
When free from water (glacial) it crystallizes at temperatures below 
6o° F. Acetic acid in dilute solution (vinegar) is much used for 
domestic purposes. For medicinal use the crude vinegar is purified 
by distillation, forming acidwn aceticum dilutum, U. S. P. 

As all the acetates are soluble, their best test is to add a strong acid 
and recognize the acetic acid set free, by its odor. 

Benzoic Acid exists in many balsams and gum -resins. When 
benzoin is heated benzoic acid sublimes in silky needles of a pleasant 
balsamic odor. Or, if the urine of herbivorous animals be boiled 



IIO ESSENTIALS OF CHEMISTRY. 

with hydrochloric acid, the hippuric acid is converted into benzoic 
acid. But the acid obtained from this source may be known by its 
urinous odor. It is now made by the oxidation of benzene, the prin- 
cipal constituent of coal-tar. 

Carbazotic or Picric Acid is a yellow substance, of a bitter taste, 
made by the action of nitric acid on carbolic acid. Used in the arts 
as a yellow dye. 

Carbolic Acid. — Already described among alcohols. 

Citric Acid exists in the juices of many fruits, especially the 
lemon. Forms colorless crystals which are very soluble, and possess a 
sour taste. Many of its salts are used in medicine. 

Formic Acid — HCH0 2 — is the oxidation product of methylic alco- 
hol. It was formerly obtained from the red ant {formica rufa), but 
now made artificially. It exists in stinging nettle, pine needles, etc., 
and also in the stings of most insects. 

Gallic Acid. — When galls are moistened and exposed to the action 
of the atmosphere, the tannic acid they contain is converted into 
gallic acid. It resembles tannic acid, but may be distinguished by its 
not precipitating a solution of gelatin. 

Lactic Acid (lactis, of milk). — This is the acid of sour milk, where 
it is formed by the fermentation of the sugar of milk through the 
agency of the casein. It is also formed in the body by the decom- 
position of glucose, thus : — 

C 6 H 12 6 — 2H 2 C 3 H 4°3* 

It is a syrupy liquid, of a very sour taste. 

Malic Acid (inalum, an apple) exists in many fruits, as apples, 
cherries, etc., and very abundantly in garden rhubarb. 

Oxalic Acid — H 2 C 2 4 . — The acid and its salts are found in many 
plants, especially the sorrel (oxalis) grasses. In certain pathological 
conditions it is formed in the body and eliminated in the urine as 
calcium oxalate. It is made in large quantities by the action of nitric 
acid on sugar, or of alkalies on sawdust. Oxalic acid closely 
resembles Epsom salts, for which it is sometimes taken by mistake. 
It is a powerful irritant poison. Being cheap and largely used for 
removing ink stains, cleaning copper, etc., poisoning by oxalic 
acid is by no means rare. Its best antidote is chalk, or some other 



PART II. — ORGANIC CHEMISTRY. Ill 

compound of calcium, with which it forms a very insoluble com- 
pound. 

Test. — Calcium chloride gives a white precipitate, insoluble in 
acetic, but soluble in hydrochloric acid. 

Pyrogallic Acid sublimes as white, feathery crystals when gallic 
acid is heated. Used in gas analysis to absorb oxygen, as a deoxi- 
dizer in photography, and as a hair dye. 

Test. — A blue color with ferrous, and a red with ferric salts. 

Salicylic Acid. — Formerly prepared from salicin, but now made 
by a patented process from carbolic acid. A very pure acid may be 
obtained from oil of wintergreen, which consists mainly of methyl 
salicylate. This, treated with potassium hydrate, forms methyl hydrate 
(methyl alcohol) and potassium salicylate ; and if to this hydrochloric 
acid be added, potassium chloride will be formed, and salicylic acid 
will fall in a mass of silky, white crystals. Salicylic acid is scarcely 
soluble in cold water, hence the salicylate of sodium is usually pre- 
scribed, which is not only more soluble, but less irritating to mucous 
membranes. 

Test. — Intense violet with a ferric salt. 

Succinic Acid was first obtained from amber (succinum), but is 
now made by fermenting malic acid. 

Tannic Acid, or Tannin. — This is the active principle of the 
vegetable astringents ; usually obtained from oak galls ; a greenish 
or brownish powder, very soluble in water, of a rough, astringent 
taste. It precipitates solutions of salts of the alkaloids and most 
metals. It precipitates gelatin and other albuminoid substances, a 
fact that explains the process of tanning raw hides. With ferric solu- 
tions tannin gives a black precipitate (black ink). 

Tartaric Acid — H 2 C 4 H 4 6 , or H 2 T. — Tartrates exist in the juices of 
many fruits. Grape juice contains much acid tartrate of potassium 
(KHT), which, being very insoluble in an alcoholic menstruum, is 
precipitated on the sides of the cask whenever the wine ferments. 
This forms argol, the principal source of cream of tartar and tartaric 
acid. Tartaric acid forms colorless crystals, very soluble, and of a 
sharp, agreeable, sour taste. 

Valerianic Acid — HC5H9O0. — This substance was first obtained 
from valerian root ; but now it is made artificially by oxidizing amylic 
alcohol by means of sulphuric acid and potassium bichromate. 



112 ESSENTIALS OF CHEMISTRY. 

Valerianic acid is a colorless liquid, possessing the disagreeable odor 
of valerian. 

The Carbohydrates. — These substances are closely related to 
the alcohols, and by some classed as such. They are so named be- 
cause they contain carbon (six or twelve atoms), and the hydrogen 
and oxygen they contain are in the exact proportion to form water. 
They constitute the bulk of plants. They are divided into three 
groups : — 

i. Amyloses (QH10O5), which include cellulin, starch, dextrin, gly- 
cogen, gums, etc. 

2. Saccharoses (C^H^On), including cane sugar, milk sugar, etc. 

3. Glucoses (C 6 H 12 6 ), such as grape sugar (glucose), fruit sugar, etc. 
Although the members of each of these groups differ widely in their 

physical and chemical properties, still they consist of the same ele- 
ments in exactly the same proportions and have the same formula. 
Such bodies are said to be isoineric. 

AMYLOSES — (C 6 H 10 O 5 ). — Cellulin — Cellulose, Lignin — forms the 
cell-walls and tissues of plants. Woody fibre, cotton, linen, and un- 
sized paper are almost pure cellulin. Dissolves in a solution of 
cupric oxide in ammonia. Acids precipitate it as a white mass, which, 
mixed with camphor and compressed, is celluloid. Unsized paper 
dipped into moderately strong sulphuric acid, washed and dried, has 
its fibres agglutinated, loses its porosity, becomes very tough, and is 
sold as artificial parchment for dialysers, diplomas, etc. 

Nitro-cellulose, or Gtm Cotton, a powerful explosive, is cotton that 
has been dipped into a mixture of nitric and sulphuric acids, and then 
washed and dried. Its solution in ether is collodion. The flexible 
collodion contains a little turpentine and castor oil ; the styptic col- 
lodion contains twenty per cent, tannin. 

Starch — Amylum — the most important member of the carbo- 
hydrates, and a valuable food ; found in the roots, stems and seeds of 
all plants. Starch is a white powder, consisting of granules, formed 
of concentric layers, like an onion. These granules have all a simi- 
lar appearance. Yet those from different kinds of plants differ enough 
to enable one, by microscopic examination, to determine the source 
of any starch (Fig. 39). 

When starch is boiled the granules swell and burst, casting the 



PART II. — ORGANIC CHEMISTRY. 



"3 



starch into the water, forming mucilage of starch, which is used for 
laundry ing and for surgical dressings. Starch is a very valuable 
food. The best test for starch is iodine, with which it forms a blue. 
Heat discharges the blue, but it returns on cooling. 

Dextrin — British Gum — is the gum used on postage stamps, etc. 
It may be made from starch in various ways, one of which is by heat- 
ing it to 300 F. It is very soluble, and gives no blue with iodine. 



Fig. 38. 




Yeast Cells. 



Glycogen — {Generator of Glucose) — is found in the animal 

economy, especially in the liver. Like dextrin, it is a derivative of 

starch, but differs from it in being soluble, and giving only a wine- 

Fig. 39. 




Arrowroot. 



Maize. 



Potato. 



color with iodine. It seems to be the form in which the carbohydrates 
are stored up, to be used by the system as necessity arises. 

Gums are a class of substances soluble in water, but insoluble in 
alcohol. A type of the class is gum Arabic. 

SACCHAROSES — C^H^Ou. — Cane Sugar — Beet Sugar, Sucrose. 
Very abundant in the sugar-cane, sugar-maple, beet-root, etc. It is 
the most soluble, perfectly crystallizable, and sweetest of the sugars, 



114 ESSENTIALS OF CHEMISTRY. 

and the one most used for domestic purposes. Its aqueous solution 
is called simple syrup (syrupus simplex}. 

Milk Sugar, as its name implies, occurs in milk ; harder, less 
soluble, and less sweet than cane-sugar. Used in the trituration of 
medicines. 

GLUCOSES — C 6 Hi 2 6 . — Glucose — Grape Sugar, Diabetic Sugar. 
■ — Found associated with other sugars in most plants, especially in the 
grape ; but the source of most interest to the physician is the animal 
economy. This is the sugar of diabetic urine, and the ability to detect 
it with ease and certainty in such conditions is a necessity to*the prac- 
titioner of the present day. 

Glucose is not so sweet nor so soluble and crystallizable as cane- 
sugar. Having great affinity for oxygen it is a valuable reducing 
agent, and on this property most of its tests depend. Boiled with a 
dilute mineral acid or allowed to remain under the influence of certain 
animal and vegetable ferments,* warm and moist, the amyloses and 

* Ferments. — These are certain nitrogenous bodies, animal and vegetable, 
which by some means not clearly understood cause many organic compounds 
to decompose with the production of other and simpler substances, the ferments 
themselves being unaffected. Ferments are of two classes : — 

1. The unorganized, or soluble ferments. Among these are: [a) Diastase, 
or maltin, formed from the gluten and serving to convert the starch of the seed 
into glucose. Malt, which is sprouted barley, contains it in abundance, and is 
used to convert meal (starch) into glucose for fermentation in the manufacture 
of alcoholic liquors, and in medicine as a digestive agent. The ptyalin of saliva 
and a pancreatic ferment act like diastase, (b) Pepsin, of the gastric juice, and 
(c) Trypsin, of the pancreatic fluid, both of which serve to convert the albumi- 
noids into peptones ; the one in acid, and the other in alkaline solution. 

2. Organized Ferments. — When their spores are carried by the atmosphere 
or otherwise into a suitable, fermentable liquid, and kept warm (68° to 105 F.), 
these ferments grow and proliferate with great rapidity, inducing fermentative 
changes in a few hours. The most important of these ferments are : (a) Yeast 
(torula cerevisice), shown in Fig. 38. This converts glucose into alcohol and 
carbon dioxide (vinous fermentation), (b) Acetic acid ferment (mycode?'ma 
aceti), commonly called " mother of vinegar," grows on solutions containing 
alcohol, which it helps to oxidize into acetic acid, (c) Thrush fungus (otdiu7?i 
albicans) grows within the mouths of ill-kept children. It induces a slight alco- 
holic fermentation. (aT) Lactic and Buty?'ic ferments go together, the one pre- 
ceding and the other closely following. These fermentations occur in intestinal 
indigestion, and the gas evolved produces flatulent colic. 

Putrefaction (the spontaneous decomposition of nitrogenous organized 
bodies) is accompanied, if not caused, by microorganisms, usually bacteria. 
Decay, on the other hand, is the gradual decomposition of organic bodies by 
the slow action of oxygen, and does not depend on living organisms. 



PART II. — ORGANIC CHEMISTRY. 115 

saccharoses are converted into glucose. The reaction consists in the 
addition of H 2 to the molecule, thus : — 

Starch. Water. Glucose. Cane Sugar. Water. Glucose. 

C 6 H 10 O 5 + H 2 = C 6 H 12 6 . C 12 H 22 O n + H 2 = 2C 6 H 12 6 . 

When starch and cane-sugar are eaten the digestive ferments (pan- 
creatin and ptyalin) convert them into glucose. The ferment (dias- 
tase), developed in a germinating seed, converts the starch into glucose, 
which is readily assimilated by the sprouting plant. 

Glucose is so easily made by boiling cellulin, but more especially 
starches, with sulphuric acid, that it has become a common adulterant 
or substitute for cane-sugar, especially syrup. This would be harm- 
less but for the fact that the cheap acid used is apt to be contaminated 
with lead, arsenic, etc. 

Glucosides. — This class includes a numerous class of neutral 
substances, mostly of vegetable origin, which, though differing greatly 
among themselves, possess one common property, viz. : When acted 
upon by a ferment or a dilute acid, they decompose, producing among 
other things, glucose. Their chemical constitution is not thoroughly 
understood, but probably they are ethers of glucose. They generally 
have marked physiological action, and are therefore the active prin- 
ciples of the drugs in which they occur. Their names generally allude 
to their origin and terminate with "-in" A few of the most important 
are : — 

Amygdalin, exists in the bitter almond (amygdala), in the leaves of 
cherry laurel, and in the seeds of peaches, cherries and plums, asso- 
ciated with an albuminoid ferment, emulsin or synaptase, which in the 
presence of heat and moisture decomposes the amygdalin into hydro- 
cyanic acid, benzaldehyde and glucose. 

Salicin is the bitter principle in the bark of the willow (sa/ix). It 
has been employed as a substitute and adulterant of quinine, from 
which it may be known by the blood red it gives with sulphuric acid. 

Tannin, or Tannic Acid, is also a glucoside. This explains why 
certain fruits, e. g., persimmons, on ripening, lose their rough, astrin- 
gent taste and get sweet. 

Myronic Acid exists in black mustard, associated with an albumin- 
ous ferment, capable of converting it into glucose and another sub- 
stance (allyl sulphocyanate) to which the virtue of mustard is due. 



Il6 ESSENTIALS OF CHEMISTRY. 

Hot water, by coagulating this ferment, renders a mustard plaster 
inert. 

Indican occurs in various plants, the indigofera ; also in urine, being 
derived from indol, a weak base produced by the pancreas and taken 
up from the alimentary canal. It is a brownish, bitter, syrupy liquid, 
which, when fermented or treated with dilute acid, forms indigo-blue 
and a kind of glucose. 

Other important glucosides are: Arbtctin, cathartic acid, colocynthin, 
digitalin, elaterin, gentianin, glycyrrhizin (licorice), ja lap in, santonin, 
saponin, solanin, etc. 

Nitrogenous Bodies. — To the physician these are of extreme 
interest, for to this class belong most of the tissues and waste products 
of the body and of our most potent remedies and virulent poisons. 

Proteids — Albumin, Globulin, Vitellin, Casein, Fibriii, Pepto7ies, 
Gelatin, Chondrin, etc. — These substances, formed in plants and ap- 
propriated by animals, constitute the greater part of the solid portion 
of the fluids and tissues of the body, and play the chief part in 
physiological processes. Their molecular constitution (rational for- 
mula) is not definitely known, but their composition seems to be 
C 72 Hi 12 Ni 8 S. They are amorphous, colloid (not crystalline) and, except 
peptones, are not osmotic (do not diffuse through animal membranes). 
When dry, they are easily preserved, but when moist, prone to putrefy. 
They are rendered insoluble by various substances, by which means 
they are often recognized. 

Tests. — (i) They are all precipitated by alcohol in excess and in 
time coagulated. (2) Heated with strong nitric acid they turn yellow, 
and on the addition of an alkali (ammonia, soda or potash) become 
orange. 

Bodies of the Ammonia Type. — Taking the molecule of ammo- 
nia, NH 3 , as a basis, and by substituting for one or more atoms of its 
hydrogen one or more organic radicals, or combinations of radicals, 
we can obtain a large number of interesting and important substances. 
Many of these substances have trade names in allusion to some use 
or property, or in abbreviation of their chemical names. In chemistry 
they bear the names of the radicals entering into their composition, 
and end in (( -a?nine" when those radicals are electro-positive, or in 
if -a7nide" when electro-negative. For example : — 



PART II. — ORGANIC CHEMISTRY. 



117 



Antilles — 



Ammonia. 



IH 



N 



Ethylamine. 

C 2 H 3 (ethyl) 
H ; 
H 



N 



Phenylamine. 

C 6 H 5 (phenyl) 

H ; 

H 



N 



Trimethylamine. 
' CH 3 (methyl) 

CH 3 

CH 3 



etc. 



Like ammonia, these bodies are alkaline and combine with acids to 
form salts, appropriating instead of displacing their hydrogen, e.g. 
NH 3 + HC1 = NH4CI, ammonium chloride or ammonia hydrochlo- 
ride ; in like manner NH 2 (QH 5 ) + HC1 = NH 2 (QH 5 )HC1, ethylamine 
hydrochloride. 



Amide s- 








Ammonia 


Acetamide. 


Acetanilide 


Carbamide 


(Amine). 




(Phenyl Acetamide). 


(Urea). 


f H 


r H 


f H 


f H 


1SNH; 


N4 IT ; 


NJC 2 H 3 ; 


Ni h 


lH 


(C 2 H 3 (acetic rad.) 


(.C.H, (phenyl) 


I >co 



Aniline (Phenylamine) is a colorless liquid, but its compounds 
( C H - ( me aniline dyes) are coloring matters of great brilliancy.* 

NJH They are sometimes contaminated with arsenic used in 

I H their manufacture. 

Trimethylamine is sometimes confounded with propylamine. It 
fCH i s a colorless, volatile alkaloid, with an ammoniacal, fishy 

N \ CH a odor. It is found in many animal and vegetable sub- 
stances, but obtained from pickled herring. The hydro- 



CH, 



N^ H 



C 6 H o 



chloride is the salt used. Dose, ten to fifteen grains. 

Antifebrin (acetanilide). This is a derivative of aniline in which 
the acetic radical is made to displace an atom of 
hydrogen. A crystalline, odorless, solid, slightly solu- 
ble in warm water, very soluble in alcohol. % In doses 
of five to ten grains, repeated every two or three hours, it is an anti- 
pyretic and sedative. It is said not to affect the healthy temperature, 
but to rapidly lower a fever. 



C 2 H 3 2 



* Experiment. — Dissolve a few drops of aniline in water in two test-tubes. 
To one add solution of chlorinated lime — a purple color is produced; to the 
other add some sulphuric acid and potassium chromate mixture — a blue color 
appears. 



Il8 ESSENTIALS OF CHEMISTRY. 

Phenacetine. The formula shows that this substance is closely 

(C 6 H 4 O C 2 H 5 allied to acetanilide. A white crystalline 

NJH powder, but slightly soluble in water. In 

(_C 2 H 3 doses of fifteen grains it causes a fall of tem- 

perature and a profuse sweat. Its effect is more persistent, and per- 
haps more dangerous than antipyrin, producing symptoms of aniline 
poisoning with hemoglobinuria and jaundice. 

Antipyrine, C 1:L H 12 N 2 0, a derivative of the artificial alkaloid, 
chinoline, is a white crystalline powder, soluble in water and alcohol, 
of a slight tarry taste and odor. With nitrous acid it forms a poison- 
ous precipitate, and is therefore incompatible with spirits of nitrous 
ether. The hydrochloride is the salt used. In doses of ten to fifteen 
grains it is a valuable antipyretic and anodyne. 

Alkaloids (alkali-like). — These bodies are mostly of vegetable 
origin and bear a close analogy to the preceding, for they are 
ammonia substitution compounds, alkaline in reaction, 'and combine 
with acids to form salts. Of late years chemists have made substances 
very similar to, if not identical with, some of the natural alkaloids ; 
and the time seems not far distant when our most costly alkaloids will 
be made cheaply by artificial means. In plants alkaloids are not 
found free, but combined with some vegetable acid forming a salt. 
Their salts (except tannates) are usually soluble and intensely bitter ; 
the free alkaloids being much less soluble, are much less bitter. 
Those alkaloids (as conine and nicotine) that contain no oxygen are 
liquid ; but the great majority of them are white powders. 

Alkaloids are so seldom prescribed in the free state that when the 
simple name of an alkaloid is written in a prescription the druggist 
puts up its most common salt. The names of alkaloids end in "-zW," 
and are derived from the names of the plants in which they exist or 
from some characteristic property. 

The intense effect alkaloids exert on the animal organism makes 
them generally the active principles of the drugs in which they are 
found. But the active principle of a drug is not always an alkaloid. 
The alkaloids include the majority of our most potent remedies and 
powerful poisons. Tannin is a common antidote, but most important 
is the prompt evacuation of the stomach and the intelligent use of 
physiological antagonists. 

The alkaloids, even those of medical interest, are so numerous that 



PART II. — ORGANIC CHEMISTRY. 



II 9 



to give each separate consideration would cover a great portion of the 
materia medica. We can mention but a few of the most important. 



Name. 



Formula. 



Source. 



Remarks. 



Morphine 
Codeine 
Narcotine 
Narceine 

Apomorphine 

Quinine 

Quinidine 

Quinicine 

Quinoidine 

Cinchonine 

Cinchonidine 

Cinchonicine 

Strychnine 

Brucine 

Aconitine 

Colchicine 

Veratrine 

Atropine 

Hyoscyamine 

Homatropine 

Caffeine 

Theine 

Cocaine 

Physostigmine 

(Eserine) 
Pilocarpine 
Urea 

Nicotine 
Conine 



C 22 H 23 NO, 



^21 22-^2^2 
^23 "26^* 2^4 

C.,„H 47 NO, 
C 17 H 19 N0 5 

C n H 2 „N0 3 
C 15 H 23 N0 3 
C 16 H 22 NO s 



C 15 H 21 N 3 2 



CH 4 N 2 

C 5 H,N 
C 8 H 15 N 



Opium 



Morphine 



Cinchona 
bark 



Nux vomica 



Aconite 

Colchicum 

Veratrum 

Belladonna 

Hyoscyamus 

Atropine 

Coffee 

Tea 

Coco leaves 

Physostigma 

(Calabar bean) 

Jaborandi 

Urine 

Tobacco 
Hemlock 



Crystalline; morphia gives a blue 
with Fe 2 Cl 6 , and a red with 
HNO3. These alkaloids and 
several others exist in opium in 
combination with meconic acid, 
which gives with Fe 2 Cl 6 a red 
color not discharged by HgCl 2 . 

Made by heating morphine with 
HC1 ; a systemic emetic. 

All crystalline except quinoidine, 
which is a resinous mass. To 
test for quinine, add chlorine 
water, shake, and then add aq. 
ammonia; a green color. 

Crystals; gives a purple with 

H 2 S0 4 and K 2 Cr 2 O r 
Crystals; gives a red with HN0 3 . 

Crystals ; very poisonous. 

Crystals; used to dilate the 
pupils. 

Crystals ; soluble in water ; weakly 

basic. 
Crystals ; soluble in water ; weakly 

basic; anodyne. 
Crystals ; soluble in water ; weakly 

basic ; local anaesthetic. 
Crystals; contracts the pupils. 

Crystals ; a powerful diaphoretic. 
Crystals ; may be made artificially 

by heating NH 4 CNO. 
Liquid ; powerful poison. 



Ptomaines (tttw/zg, a corpse). — This name is given to certain alka- 
loids or amines formed in animal and some vegetable bodies during 
putrefaction, and in some pathological conditions during life. These 



120 ESSENTIALS OF CHEMISTRY. 

are the products of bacteria, each species producing its own peculiar 
ptomaine. Thus, the typhoid-bacillus produces typhotoxine ; the 
tetanus-bacillus, tetanine, etc. Many think the symptoms of the spe- 
cific fevers are only the effects of the ptomaines so produced, for the 
characteristic symptoms of the disease may be produced by the ad- 
ministration of its ptomaine. The poisoning that frequently results 
from eating spoiled meat, fish, etc., is due to ptomaines. The symp- 
toms resemble those of the vegetable alkaloids, except that there is usu- 
ally more gastro-intestinal irritation. The fact that certain ptomaines 
give physiological effects and chemical tests like such alkaloids as 
strychnine, morphine, conine, nicotine, atropine and veratrine, is apt 
to, and doubtless has often, caused the condemnation of the innocent. 

Among the non-poisonous ptomaines may be mentioned putrescine, 
cadaverine and neuridine. Among the poisonous are : choline, 
which acts like curarine ; muscarine, from poisonous mushroons (mus- 
carius) ; tetani?ie, teta,7iotoxine and spasmotoxine, produced by the 
tetanus-bacillus and causing (?) the symptoms of tetanus ; typhotoxine, 
produced by the typhoid-bacillus and causing (?) the symptoms of 
typhoid fever, and tyrotoxine, found by Dr. Vaughan in poisonous 
cheese and milk and causing the symptoms of cholera infantum. 

Leucomaines are a class of alkaloidal substances produced in the 
living body as the result of fermentative changes or of the processes 
of retrograde metamorphosis, and are closely related to urea and uric 
acid. They are eliminated in the various excreta, the urine, faeces, 
perspiration, etc. If retained, as in uraemia, or produced in abnor- 
mal amounts, as in dyspepsia, they act deleteriously on the nerve 
centres causing vertigo, lassitude, drowsiness, vomiting, purging and 
coma. Some elevate while others lower the temperature. Of the 
more important we may mention creatine, creatinine and xanthine. 

The chemistry of the ptomaines and leucomaines is new and still 
incomplete. 



PART III. 



THE URINE 



Fig. 40. 



The urine is a fluid secreted continuously by the kidneys, and is 
the chief means by which the nitrogenous waste of the body is dis- 
charged.* A specimen, to be representative, should be a portion of 
the whole twenty-fours' urine, for considerable 
variation in composition and properties may 
occur during the day. Especially is this true of 
traces of albumin and sugar. When this is 
impracticable, that passed before breakfast is 
generally preferable, because farthest from a 
meal. When significant variations during the 
day are suspected, several specimens may be 
taken at different hours. For microscopical ex- 
amination a few ounces of the urine in a stop- 
pered vial, or better still, in a covered conical 
glass (Fig. 40) are set aside for several hours until the sediment has 
settled to the bottom and can be examined. 




<S.il£MANN-CQ. 



*The rationale of its secretion is one of transudation, osmosis, and cell 
elaboration. Owing to the resistance encountered by the blood in its exit 
through the efferent vessel, there is an increase of blood-pressure in the Mal- 
pighian tuft and a transudation of the water of the blood with some dissolved 
salts into the capsule. From loss of water the blood is very much thickened 
when it reaches the second capillary system surrounding the convoluted tubes, 
which contain the thin, watery transudation from the Malpighian bodies. 
Here are the essential elements of a complete osmometer — an animal mem- 
brane, composed of the thin wall of the capillary and the delicate basement 
membrane of the tube, with a dense fluid (the thickened blood) on one side 
and a thin saline solution on the other. An interchange now takes place of 
the water from the tube to the blood, and of the products of retrograde meta- 
morphosis (urea, etc.), and salts from the blood to the tubes, concentrating the 
fluid in the latter, making it urine, while the albuminous constituents of the 
blood, not being osmotic, are retained. An elaborative function has long been 



122 ESSENTIALS OF CHEMISTRY. 

Physical Properties. — Normal urine is a transparent, aqueous 
fluid, of a pale yellow color, characteristic odor, acid reaction, and a 
specific gravity of 1020 when passed in the average quantity of about 
forty-five fluid owtces in the twenty-four hours. This description is 
to be taken with much allowance, for very wide variations occur even 
in health. With these variations the student must become thoroughly 
familiar before he is capable of interpreting a specimen. Therefore 
the physical properties will be considered more particularly. 

Quantity. — In health this depends upon (a) the amount of water 
ingested, and (b) its vicarious elimination* by the skin, lungs, and 
bowels. Pathologically it is increased in diabetes, also in hysterical 
conditions associated with convulsions and high arterial pressure, and 
after the administration of diuretics. 

Transparency. — Normal urine is not always transparent, nor is 
transparent always normal. Some degree of opacity may be due to : 
{a) Mucus, with some entangled epithelial cells, which may be 
observed in many specimens of healthy urine, especially of females, 
because of the larger area of mucous surface in that sex. (b) Urates 
(of Na, K, Ca, and Mg), which often form a precipitate in urine, 
especially when allowed to stand over night in a cold room. The test 
for this sediment is heat, which quickly dissipates it. (c) Earthy phos- 
phates (of Ca and Mg), which may give an opacity to normal urine, 
especially if it is alkaline or even weakly acid. The test for this 
sediment is the addition of a few drops of any acid which promptly 
clears it up, while heat would only increase it. (d) Fungi (bacteria, 
penicillia, sarcinae, etc.), especially in decomposing urine. 

A urine may be abnormally opaque from the above causes, or from 
the presence of blood or pus. When due to blood or pus the opacity 
is increased by heat or acids because of the precipitation of albumin 
always present in liquor sanguinis and liquor puris. 

Fluidity. — Healthy urine is never otherwise than an aqueous fluid, 

attributed to the epithelial cells lining the convoluted tubes, for it was observed 
that whenever the tubes lost their epithelial lining (as in some forms of Bright' s 
disease), urea, etc., failed to be eliminated. This function of the cells may be 
demonstrated by injecting .into the veins of a rabbit a solution of sulph-indigo- 
tate of sodium. If the animal be killed within a few minutes, none of the 
coloring matter will be found in the capsules, while the cells lining the tubes 
will be stained blue. If, however, an hour be allowed to elapse, even the 
cells will be found colorless and the coloring matter will be seen only in the 
urine. 



PART III. — THE URINE. 1 23 

flowing and dripping with ease ; but in certain diseased conditions, 
abnormal quantities of mucus, or the presence of pus or fat, especially 
if the urine be allowed to decompose and become very alkaline, may 
give rise to viscidity. 

Color. — Healthy variations in color depend mainly upon the 
amount of water and the consequent degree of concentration or dilu- 
tion of the solid constituents. Aside from abnormal degrees of the 
above, pathological variations in color may be the result of {a) an 
increase or diminution of the normal coloring matters, as in fevers, 
etc. ; (b) the presence of abnormal substances, as biliary and blood 
coloring matters. Moreover, the urine may be colored after the 
administration of certain drugs, as senna, santonin, rhubarb, prickly 
pear, etc. 

Odor. — When freshly passed, urine has, in addition to its charac- 
teristic odor, an aromatic fragrance due to certain volatile ethers. 
Alkaline urine has an ammoniacal odor, unless the alkalinity be due 
to fixed alkali, when the smell is fainty and sickening, like that of 
horses' urine. Diabetic urine exhales a sweetish smell. In certain 
forms of dyspepsia and liver trouble, the odor of the urine is almost 
pathognomonic. Medicines and certain articles of food often impart a 
peculiar odor, as turpentine the odor of violets, and asparagus and 
cauliflower a rank, disgusting smell. 

Reaction. — Normally the urine of the whole twenty-four hours will 
average an acid reaction ; but great variations occur during the day. 
Before meals it will have a high degree of acidity, but after eating 
becomes nearly neutral, or even alkaline. This is due to the ingestion 
of food which is largely alkaline and to the abstraction of acidulous 
principles from the blood to form acid gastric juice. It has also been 
observed that urine passed on rising in the morning is especially acid. 
This is probably due to the fact that during sleep less carbonic acid is 
exhaled from the lungs and less perspiration (acid) given off by the 
skin. The reaction of the urine is important to the physician, as it 
may favor or prevent the formation of sediments and concretions or 
irritation of the kidneys and bladder. The acidity of urine is due, not 
to free acid, but to acid sodium phosphate (NaH 2 P0 4 ) occurring in con- 
sequence of carbonic, uric, and hippuric acids, seizing on to a portion 
of the sodium of the basic phosphate. 

An acid fermentation, attended with decomposition of mucus and 
coloring matters and a production of acetic and lactic acids, some- 



124 



ESSENTIALS OF CHEMISTRY. 



times occurs in urine that has stood for some time at a moderate tem- 
perature. After a while, more quickly in warm weather, the alkaline 
fermentation begins, caused by the development of the micrococcus 

Fig. 41. 




Acid Fermentation. 
Fig. 42. 




Alkaline Fermentation. 



ureae (Pasteur). The urea is converted into ammonium carbonate, 

thus : — 

CH 4 N 2 + 2H 2 = (NH 4 ) 2 C0 3 . 



PART III. — THE URINE. 



125 



This gives the urine an ammoniacal odor and alkaline reaction, and 
it becomes opaque from the precipitation of urate of ammonium and 
the earthy phosphates and the development of bacteria. Pus and 
blood, or vessels tainted with urine previously fermented, greatly 
hasten this change. 

The reaction is determined by litmus paper. If acid, the blue 
litmus is turned red ; if alkaline, the red litmus is turned blue ; if 
neutral, there is no change in either. If alkalinity be due to ammonia 
(volatile alkali), the blued paper gets red again on drying. 

Specific Gravity. — Though the average specific gravity is 1020, it 
exhibits, even in health, great variations, the extremes being 1002 
after copious use of water and diuretics, and 1040 after abstinence 
from fluid and the elimination of water through other means, as pro- 
fuse perspiration or copious diarrhoea. The amount of solids varying 
but little in health, fluctuations in specific gravity are due mainly to 
variations in the amount of water, and, as long as the inverse propor- 
tion between specific gravity and volume of urine is preserved, varia- 
tions need cause no alarm. 

Specific gravity is usually measured by an instrument called a 
hydrometer or urinometer (Fig. 43), which is a hollow glass float, 
weighted with mercury and having a long, graduated neck. The 
graduation begins above at 1000, because the heavier the urine the 
less deeply will the instrument sink and the further the neck will pro- 
trude from the surface. It is well to test a new urinometer by immer- 



Fig. 43. 



sing it in water at 6o° F. (15. 5 C), into which it 
should sink to o or 1000 on the scale. Urinometers 
are usually provided with a cylinder or jar, as shown 
in the figure, but a large test-tube will answer. This 
is about three-fourths filled ; the urinometer is then 
introduced, and when still, the specific gravity is read 
off. The cylinder or test-tube should not be too 
narrow, lest the urinometer be 
attracted to and catch against 

the sides, and not rise as high c 

or sink as low as it should. The « ' ™ "- 

fluid being attracted up around 
the stem, the reading should be 
made not along the line c d, as 
in the diagram, suggested by Dr. Leffmann, of Philadelphia, but a b, 




126 ESSENTIALS OF CHEMISTRY. 

which represents the true level of the liquid. To approximate the 
amount of solids in any urine : (a) The last two figures of the specific 
gravity represent the number of grains of solids to the fluid ounce ; 
(&) doubling the last two figures of the specific gravity, gives the per 
cent. Thus, if a urine be of specific gravity 1020, and the daily volume 
fifty ounces, (a) 20 (grains per fluid ounce), multiplied by 50 (ounces 
daily volume) gives 1000 grains of solids per diem ; (6) .020 X 2 = .040 
or 4 per cent., which multiplied by 50 (ounces daily volume) gives 2 
ounces of solids per diem. 

Chemical Constituents. — The average composition of a thousand 
parts of urine is about as follows : — 

Water, 950.00 

Urea, 26.20 

Kreatine and kreatinine, 80 

Urates of sodium and potassium 1.45 

Hippurates of sodium and potassium, 70 

; Mucus and coloring matters 35 

Phosphates of sodium and potassium, .... 3.75 
Phosphates of calcium and magnesium, . . . .90 

Chlorides of sodium and potassium, I2 -55 

Sulphates of sodium and potassium, 3.30 



6 



Pathologically there may be present also albumin, glucose, blood, 
bile, etc., besides various sediments. 

Urea — CH 4 N 2 0. — This is the most constant and abundant organic 
constituent of the urine, and, being the main nitrogenous excretion, 
it is the index of nitrogenous waste, whether of food or tissue. Its 
average amount is about one ounce per diem. 

Urea may be obtained by extracting it from the urine, or artificially 
by heating cyanate of ammonium with which it is isomeric (NH 4 - 
CNO = CH 4 N 2 0). 

It crystallizes in colorless prisms, very soluble in water, and behaves 
like an alkaloid, combining readily with nitric and oxalic acids to 
form salts. Both of these salts may, by adding nitric or oxalic acid, 
be precipitated from concentrated urine as colorless, rhombic or 
hexagonal plates. (Fig. 44, c.) 

In the course of many diseases it is important to estimate the 



PART III. — THE URINE. 



127 



amount of urea excreted day by day. A rough estimate may be based 
on the specific gravity. For, since urea is the largest solid ingredient 
in urine, it follows that if sugar be absent, albumin in small amount 
or removed, and the amount of chlorides normal, variations in specific 
gravity must be due mainly to variations in amount of urea. 

The exact methods most generally employed consist in decompo- 
sing the urine into nitrogen and carbon dioxide, by means of sodium 
hypochlorite or hypobromite, and measuring either the volume of gas 
evolved or the specific gravity lost by the decomposition. 

Fig. 44. 




(a) Urea; (b) hexagonal plates ; and (c) smaller scales, or rhombic plates of Urea Nitrate. 



Davy's Hypochlorite Method, — A graduated tube closed at one end 
is one-third filled with mercury. A measured quantity of the urine (a 
drachm or half drachm, according to capacity of tube) is then added, 
and the tube is next filled to the brim with the hypochlorite solution (liq. 
sod. chloratse, U. S. P.). Closing the opening with the thumb, the 
tube is inverted over a strong solution of common salt in a dish. (Fig. 
45.) The mercury runs out and the salt water rises to take its place, 
while the urine and soda mixture, being lighter, remain in the upper 
part of the tube. Here the gas from the decomposing urea collects. 
The decomposition is complete in three or four hours, when the 



128 



ESSENTIALS OF CHEMISTRY. 



amount of the gas may be read off by the graduations upon the tube, 
every cubic inch representing .64 grain (or 1 cubic centimetre repre- 
senting 2.5 milligrams) of urea. 

Doremus Hypobromite Method. — The sodium hypobromite is pre- 
pared by adding 1 cubic centimetre of bromine to 10 cubic centimetres 
of sodium hydrate solution (100 grammes to 250 cubic centimetres of 
water, or 6 ounces to 1 pint) and diluting with 10 cubic centimetres of 
water. Tilt the ureometer (Fig. 46), and pour the hypobromite into 
the long arm, completely filling it. Draw the urine to be tested into 



Fig. 45. 



Fig. 46. 












the pipette to the graduation. Pass the pipette into the ureometer as 
far as the bend, and compress the nipple slowly. The urine will rise 
through the hypobromite, and the gas evolved will collect in the upper 
part of the tube. The ureometer is graduated to indicate either the 
number of milligrammes of urea to the cubic centimetre of urine or 
the number of grains to the fluidonnce. 

Fowler's Method. — The specific gravity of the urine is carefully deter- 
mined as well as that of the liq. sodae chloratae (U. S. P.) to be used. 
One volume of the urine is mixed with exactly seven volumes of the 
liq. sod. chlor. and set aside for two hours, or until effervescence ceases. 
The specific gravity is again taken. As the reaction begins immedi- 



PART III. — THE URINE. 1 29 

ately on mixing the fluids, the specific gravity of the mixture must be 
calculated. This is done by adding to the specific gravity of the urine 
seven times that of the liq. sod. chlor. and dividing the sum by eight. 
Each degree of difference in specific gravity of the mixture before and 
after the decomposition represents three and a half grains of urea to 
the fluidounce of the day's urine. 

Example: — Ounces. 

Quantity of urine in twenty-four hours, 46 

Sp. gr. of the urine, 1020 

Sp. gr. liq. sod. chlorate, 1042 

(Calculated) Sp. gr. mixture ( 1042x7+1 110 =),... 1039.2 + 

(Actual) Sp. gr. mixture after reaction, 1036.2 

1039.2 — 1036.2 = 3 ; 3 X 2> l A = 10X grs. of urea to the ounce of 
urine ; 10^ X 46 = 483 grs. of urea passed in twenty-four hours. 

Kreatine and Kreatinine, substances closely allied to urea, 
exist in urine in such small amounts as to be of no practical signifi- 
cance, and need only to be mentioned in this connection. 

Uric Acid is found in the urine of carnivora : in that of herbivora 
it is largely replaced by an analogous substance — hippuric acid (Fig. 
55). Gout is characterized by an increased production of uric acid, 
and the so-called '' chalk-stone " deposit in joints during that disease 
is sodium urate. Free uric acid is so very insoluble that whenever it 
exists in urine it is always a precipitate. It appears as minute reddish 
grains, which under the microscope are seen to be modifications of 
rhombic crystals, always stained with the coloring matter of the urine. 
They often deviate widely from the typical rhomb, as shown in Figs. 
47 and 48, but an experienced eye will readily recognize them. Nor- 
mally, uric acid, as soon as formed, unites with the alkaline bases to 
form urates. They are very soluble in warm water, but more sparingly 
so in cold. Therefore a urine, though clear when freshly passed and 
warm, may exhibit a copious precipitate upon becoming cold, as on a 
winter night. This precipitate is easily recognized by its dissolving 
upon warming. Urates of sodium and magnesium generally appear 
under the microscope as amorphous powders in moss-like aggrega- 
tions, but occasionally as bundles of small needles, as shown in Fig. 
49. The urate of ammonium, a result of the alkaline fermentation, 
occurs as opaque, brown spherules, smooth or with spiculse like a 



13° 



ESSENTIALS OF CHEMISTRY. 



thorn-apple (Fig. 42). The acid urates are less soluble than the 
normal, and often precipitate when the urine is very acid or when an 
acid is added, as in the nitric-acid test for albumin. 

The murexid test for uric acid and the urates is one of great beauty. 
Place some of the sediment in a porcelain dish, add a drop or two of 
nitric acid, and carefully evaporate almost to dryness. If a few drops 
of ammonia be added, it assumes a beautiful purple color. 

If uric acid be present, a beautiful purple color will appear when- 
ever a few drops of ammonia are added ; or better still (Earp), if the 
dish be inverted over another in which a dry ammonium salt is vola- 
tilized. 

Fig. 47. Fig. 48. 




■>Fl 
0>M' 








Uric Acid. 



Uric Acid. 



Coloring Matters. — Our unsatisfactory knowledge of these sub- 
stances and their clinical significance is to be regretted, since some 
of them possess an importance next to albumin and sugar. The 
existence of at least two distinct substances have been demonstrated : — 

1. Urobilin (tirohcematiii), a brown resinous substance, derived 
from the coloring matter of the bile, and hence indirectly from the 
coloring matter of the blood. 

It occurs in normal urine, and in larger quantity in the urine of 
patients suffering from any disease which causes disintegration of 
the blood corpuscles. 

2. Uro-indican (tiroxanthin) a substance closely related to, if not 
identical with, the glucoside indican, and, like that substance, it is 
capable of conversion into indigo-blue. 



PART III. — THE URINE. 



131 



It seems to be a result of the fermentation of albuminous matters in 
the alimentary canal. It is therefore increased in obstructive troubles 
of the bowels, and in certain diseases characterized by impairment 
of general nutrition. 

To estimate the coloring matters, put some urine in a beaker and 
render it strongly acid with nitric or hydrochloric acid. Let it stand 
six hours for the pigments to be liberated. Then note the depth of 
color by transmitted light. 

Phosphates. — The phosphates are derived mainly from the food, 
but to some extent also from oxidation of phosphorized tissues : — 

1. Earthy Phosphates (Ca and Mg). — Being soluble only in acid 

Fig. 49. 




Urates. Oxalate of Calcium. 



solutions, the earthy phosphates are precipitated when the urine is 
made or becomes alkaline. Furthermore, being less soluble in warm 
than cold urine, heat often precipitates them, as in the heat test for 
albumin. Deposits of calcium and magnesium phosphates are gen- 
erally amorphous, and may be distinguished from the amorphous 
urates, (a) by absence of color and not gathering in mossy forms ; (J?) 
by a drop of acetic acid added to the sediment on a glass slide under 
the microscope — phosphates dissolve, while urates gradually lose their 
base and assume the characteristic forms of uric acid. In ammoniacal 
urine (alkaline fermentation) the ammonio-magnesian phosphate 
(MgNH 4 P0 4 ), the so-called triple phosphate, is formed and deposited 
in large prismatic, coffin-lid crystals ; sometimes, also, in ragged 



132 



ESSENTIALS OF CHEMISTRY. 



stellate or aborescent crystals, resembling those of snow. (Fig. 50.) 
In cases of cystitis this may occur within the bladder ; hence other 
calculi often have one or more white layers of the mixed phosphates. 

2. Alkaline Phosphates. — These constitute the greater portion of 
the phosphates, and are made up mainly of acid sodium phosphate, 
with traces of potassium phosphate. Being very soluble, they never 
form a precipitate. 

Magnesian Test. — The phosphates are best detected and estimated 
by precipitation with a solution composed of magnesium sulphate, 
ammonium chloride, and aq. ammonise, each one part, and water 
eight parts. If the precipitate be thick and creamy, the phosphates 

Fig. 50. 




Triple Phosphate. 



are abnormally increased ; if it be milky, they are normal, and if 
translucent, diminished. 

Chlorides. — These consist almost entirely of sodium chloride, the 
quantity depending mainly on what is taken in with the food. How- 
ever, the chlorides are diminished or even disappear from the urine in 
many fevers, especially in pneumonia, much being eliminated by the 
sputa. Their reappearance in the urine is often the earliest indica- 
tion of convalescence. Hence their detection and estimation are 
important. 

Silver- Nitrate Test. — First add a few drops of nitric acid to prevent 
the precipitation of the phosphates. Then, on adding silver nitrate 
solution, only the chlorides will fall as a white precipitate of chloride 



PART III. — THE URINE. 1 33 

of silver. If the precipitate be in curdy masses the chlorides are not 
diminished ; if only a milkiness be produced, they are greatly dimin- 
ished ; and, if no cloudiness, they are entirely absent. 

Sulphates. — These consist mainly of sodium sulphate, with a little 
of the potassium salt. They are derived principally from the food, 
and in small amount from oxidation of albuminoid sulphurized tissues, 
especially in fevers. They are detected and estimated by precipita- 
tion with barium chloride or nitrate, first adding a little nitric or 
hydrochloric acid to hold the phosphates in solution. If the precipi- 
tate be creamy the sulphates are increased ; if milky, normal, and if 
translucent, diminished. 

Albumin. — Under this head are included various proteid substances 
which, not being osmotic, appear in urine only in pathological con- 
ditions and functional disturbances. Many of the specific fevers, as 
pneumonia, typhoid, and diphtheria, produce albuminuria. Albumi- 
nous urine is apt to be of diminished transparency from presence of 
tube casts, fat granules, epithelial cells, etc., and filtering is often 
necessary before applying the tests. 

Heat Test. — A test-tube is one-third filled with the suspected urine 
and held in the flame of a spirit lamp, or over the chimney of an 
ordinary lamp, until it boils. If an opacity occurs it must be either 
albumin or earthy phosphates. If earthy phosphates, it clears up on 
addition of nitric acid, but if albumin, it is slightly increased. 

Nitric- Acid Test. — This consists in underlaying the urine with nitric 
acid. Take a test-tube one-fourth full, and, holding it aslant, gently 
pour in an equal volume of the acid, allowing it to trickle down the 
inside of the tube and pass beneath the urine. Or the acid may be 
put in first and the urine added afterward. An opacity at the junction 
of the two liquids is either albumin or the urates. If urates, it clears 
up on heating, but if albumin, it is permanent. 

Either the heat or nitric-acid test, singly, is unsatisfactory, but both 
performed together are conclusive. However, the following sources 
of error should be borne in mind : (a) If the urine be very alkaline 
and the amount of albumin small, heat will cause no opacity ; (U) if 
only a drop or two of nitric acid be added, it may hold a small quan- 
tity of albumin in solution ; (c) urea may be precipitated from a con- 
centrated urine by nitric acid, but heat dissolves it ; (d) decomposed 
urates containing ammonium carbonate effervesce on addition of an 



134 ESSENTIALS OF CHEMISTRY. 

acid; (e) often after taking turpentine, copaiba, etc., nitric acid pre- 
cipitates resin in yellowish flakes, redissolved on addition of alcohol. 

Other Tests. — Many other substances, as alcohol and certain acids 
and mineral salts, coagulate albumin and are used as tests for that 
substance. But they are less used, less convenient, and no more 
accurate and conclusive than the two already given. Among them 
may be mentioned (a) picric acid, (b) potassio-mercuric iodide (KI 50 
grs. — HgCl 2 21 grs.), (c) sodium tungstate, (d) potassium ferrocyanide. 
These added in saturated solution form white clouds with albumin, 
provided the urine is first acidulated with citric acid. Strips of filter 

paper steeped in these chemicals and dried, or pellets, are 

sometimes carried for use at the bedside. 



Quantitative Esfanation. — During the progress of a disease 
it is often important to estimate the quantity of albumin. 
The exact method by drying and weighing the precipitated 
albumin is too laborious for the busy practitioner. 

The easiest approximative method is to precipitate the albu- 
min by heat, set it aside for twelve hours or until next visit, and 
then note the proportion of volume occupied by the precipi- 
tate — one-fourth, one-eighth, a trace, etc. 

EsbacJis Albumino?neter (Fig. 51) is a graduated test-tube. 
Fill it to U with the urine and to R with the reagent, which is 
composed of 10 grammes of picric acid, 20 grammes of citric 
acid, and water sufficient to make a liter. Gently mix the 
liquids and set aside for twenty-four hours, to allow the precipi- 
tate to subside, the depth of which by the scale indicates the 
number of parts per thousand or grammes of albumin in a liter. 

Sugar (Glucose). — It has been proven (Dr. Pavy, 1879) tnat healthy 
urine contains traces of glucose, but quantities of clinical significance, 
and appreciable by the ordinary tests, are present only in glycosuria 
or diabetes, a pathological condition associated with some disturbance 
of the glycogenic function of the liver. 

A temporary glycosuria may occur after the administration of 
anaesthetics and in certain brain lesions, especially those involving 
the floor of the fourth ventricle. 

High specific gravity in a urine pale and copious, suggests sugar. 
Before testing, albumin, if present, should be removed by boiling and 
filtration. 

Fermentation Test. — Two vials — one for comparison, the other for 



PART III. — THE URINE. 1 35 

fermentation — are partly filled with the urine. Into one is put a bit 
of baker's yeast about the size of a pea. Both vials are loosely plugged 
with some pervious material, as cotton, and set aside where they will 
keep warm (6o° or jo° F.) until next day or next visit. If sugar be 
present, fermentation will occur in the vial treated with yeast, and C0 2 
bubbles up and passes off through the cotton plug, and on taking the 
specific gravity of each, there will be a difference due to the loss of 
sugar in the vial fermented. 

- Alkali Test. — Boil the urine with liquor potassae or sodae, and if 
glucose be present it will be oxidized and form a molasses-like colora- 
tion, the depth of which indicates the amount of sugar present. On 
adding nitric acid a molasses-like odor is developed and the coloration 
discharged. 

Alkali- Copper Test. — This depends on the power glucose has of 
reducing the cupric to the cuprous oxide. There are several methods 
of performing this test : — 

(i) Trom?ner's. A drop or two of a weak (about i to 30) solution 
of cupric sulphate is added to an inch of urine in a test-tube, and then 
an equal bulk of liquor potassae or sodae. Immediately there falls, in 
addition to the earthy phosphates, a bluish precipitate. If sugar is 
present, this precipitate dissolves on agitation, forming a blue solu- 
tion, which, on boiling, deposits a yellow, orange, or red precipitate 
of cuprous oxide. (See p. 86.) 

(2) Fehlings. This differs from Trommer's in the addition of tar- 
taric acid or some tartrate to dissolve the blue precipitate. Further- 
more, the ingredients are in definite proportion, so as to make the 
solution available for quantitative analysis. Below are given the two 
formulae in general use, one in the French and the other in the 
English measures : — 

Fehling's Solution. Pavy's Solution. 

Cupric Sulphate, 34.64 grams. 320 grains. 

Potassium Tartrate, 173.20 grams. 640 grains. 

Caustic Potash, 80.00 grams. 1280 grains. 

Water, 1 liter. 20 ounces. 

On standing a long time this solution is apt to spoil, the tartaric acid 
being converted into racemic acid, which, like glucose, will deoxidize 
the cupric oxide. Hence, it is best to make the solution in two separate 
parts, the cupric sulphate with one-half the water and the tartrate and 
caustic potash with the other half. For use, mix equal parts, forming 



I36 ESSENTIALS OF CHEMISTRY. 

Fehling's solution fresh. A convenient amount should be put in a 
test-tube and boiled alone for a few seconds. If it remains clear it is 
good, and the urine may then be added gradually. Either immedi- 
ately, or when the heat is reapplied, if sugar be present, the reddish 
precipitate will appear. Heat should not be applied longer than a 
minute, for prolonged boiling can cause the reduction of the copper 
oxide by various other organic substances found in the urine. 

(3) Haines differs from Fehling's in that glycerine is used instead 
of the tartrate, and the solution does not spoil. 

Alkali-Bismuth Test. — (1) To some urine in a test-tube add a pinch 
of bismuth subnitrate and then an equal volume of liquor potassae. 
Boil about two minutes. If sugar be present, the bismuth will be 
reduced and deposited as a black metallic mirror on the sides and 
bottom of the tube. (2) A bismuth test solution corresponding to 
Fehling's is made by warming a scruple each of bismuth subnitrate and 
tartaric acid in two ounces of water, and adding liquor potassae until 
a clear solution is obtained. This boiled with a urine containing glu- 
cose gives the black bismuth precipitate. 

The elements of the foregoing tests put up in pellets and tablets, 
while more convenient, are less reliable and spoil sooner than the 
solution. 

Picric-Acid Test. — This is an extremely delicate test for glucose, 
and has the practical advantage of being as good a test for albumin. 
To the suspected urine add an equal volume of a saturated solution 
of picric acid. A cloudy precipitate indicates albumin. Next add a 
few drops of liquor potassae and warm gently. A deep red color indi- 
cates sugar, though a lighter coloration may occur in urine free from 
glucose. 

Indigo- Carmine Test. — To the urine add a solution of indigo- 
carmine rendered alkaline by sodium carbonate. Boil, and if sugar 
be present the blue mixture changes to violet-red and yellow. On 
agitation oxygen is absorbed from the air, and the above changes of 
color are reversed. 

Qua7ititative. — (1) Fermentation, Each degree of specific gravity 
lost in fermenting represents one grain of sugar to the ounce of the 
twenty-four hours' urine. 

(2) Fehling s. Two hundred minims of the solution is decolorized 
by one grain of sugar. Two hundred minims (grains) of the test solu- 
tion are measured off into a small flask, diluted with twice its bulk 



PART III. — THE URINE. 



137 



of water, and gently boiled (Fig. 52). A graduated burette (also 
shown in figure) is then filled to zero with the urine. To the boiling 
test solution the urine is added drop by drop till the blue color is dis- 
charged. By the graduations on the burette the quantity of urine 
added is easily read. As that represents one grain of "sugar, the 
amount of sugar in the entire urine is easily calculated. 

(3) Alkali Test. A light yellow indicates one per cent. ; dark 
amber, two per cent. ; sherry wine, three per cent. ; dark Jamaica 
rum, five per cent., and dark, almost opaque, ten per cent. 

Blood gives to urine a smoky hue, or even a dark-brown color. 

Fig. 52. 




Hematuria (blood in urine) may occur as the result of (a) some dis- 
ease or injury in the genito-urinary tract, as acute nephritis, calculus, 
parasites, cancer, wounds, etc. ; (b) a depraved condition of the blood, 
as in scurvy, purpura, and eruptive fevers ; (c) a disturbance of the 
renal circulation, as in mental emotions, malarial paroxysms, and 
cardiac obstructions. 

If the urine be acid, the blood corpuscles retain their shape for 
several days and are easily recognized by the microscope. They ap- 
pear as amber-colored, biconcave disks, either single or laid in rows, 
like piles of coin. Owing to the biconcavity of the corpuscles, their 
centres and peripheries alternate in brightness and shadow, as the 
10 



138 



ESSENTIALS OF CHEMISTRY. 



object-glass is made to approach or recede. Their color and smaller 
size also serve to distinguish them from pus corpuscles. In doubtful 
cases a minute drop of blood, taken from the finger with a needle, 
may be used for comparison. After urine containing blood has stood 
for some time, the corpuscles lose their regular outline and become 
shriveled and angular. (See a in figure.) If the corpuscles be dis- 
integrated and dissolved, we must test for blood-coloring matters. 

The spectroscope offers the best means for their detection, but as 
physicians are seldom provided with that instrument, the following is 
the test : Place the urine in a test-tube and shake up with equal 
volumes of tincture of guaiacum and ozonized ether or old oil of tur- 



Fig. 53. 





© 



§*mm 



®i • « V 

® © 



Blood Corpuscles. 

pentine. If blood-coloring matters are present, the precipitated resin 
is blue, instead of a dirty greenish yellow. 

Bile. — Urine containing bile is yellow, froths on shaking, and a rag 
dipped in it and dried is permanently yellow. 

1. Test for Bile-coloring Matters* — (a) Underlay the urine with 
yellow nitric acid or a mixture of nitric and sulphuric acids ; or the 
urine and acid may be placed adjacent on a white plate. In either 



* Bilirubin oxidizes so easily that icteric urine often gives only the green 
coloration, or, if kept long, fails to respond at all. Hence, if fresh icteric urine 
cannot be obtained and bile urine must be prepared for demonstration, fresh 
bile from a recently killed animal, and not the inspissated, must be used. 



PART III. — THE URINE. 



139 



method there occurs, at the junction of the liquids, a play of colors, 
green being prominent and characteristic ; (b) overlay the urine with 
tincture of iodine. At junction of the liquids a green color will appear. 
2. Test for Bile Acids. — Add a few grains of cane sugar or glucose 
to the urine and underlay it with sulphuric acid. At the junction of 
the liquid a reddish-purple color appears. As other substances than 
the bile acids may produce this reaction, we must, in cases of doubt, 
evaporate the urine to dryness, extract with alcohol, precipitate with 
ether, and redissolve in distilled water, and then apply the test as 
above. 

Fig. 54. 




Leucin Spherules and Tyrosin Needles. 



Leucin and Tyrosin occur only in bile urine, for they attend 
destructive liver disease, especially acute, yellow atrophy and phos- 
phorus-poisoning. They form yellowish crystalline deposits (Fig. 54) 
— leucin as spherules, with concentric striae, and tyrosin as sheaf-like 
bundles of fine needles. 

Cystin is a rare urinary sediment, a yellowish deposit of hexagonal 
plates (Fig. 55), not dissolved by heat or acetic acid but readily by 
ammonia. It is a highly sulphurized body whose formation in the 
system is obscure. It sometimes forms calculi. 



140 



ESSENTIALS OF CHEMISTRY. 



Carbonate of Calcium is a very rare deposit in human, but 
abundant in the urine of cattle. It occurs in small spherules (Fig. 56) 
sometimes coalescing ; acetic acid dissolves it with effervescence. 

Hippuric Acid {Horse-uric Acid) largely replaces uric acid in the 
urine of herbivorous animals, and to some extent in that of man, 
especially after a vegetable diet. It occurs in pointed, four-sided 
prisms and acicular crystals, insoluble in acetic acid but soluble in 
alcohol. (Fig. 56.) 

Calcium Oxalate occurs in extremely small amounts in normal 
urine, but more abundantly in the so-called oxalic diathesis and in 
certain forms of dyspepsia, or after eating rhubarb or other things 



Fig. 55- 



Fig. 56. 





Cystin. 



Carbonate of Calcium. Hippuric Acid. 



containing it. If persistently present it may form a (mulberry) calcu- 
lus. It occurs in both acid and alkaline urine, and always as a light 
delicate precipitate, which under high powers is seen to consist of 
small, brilliant octahedral crystals, but sometimes dumb-bells. (Fig. 
49.) In certain aspects the smaller octahedra appear as squares 
crossed by two bright diagonal lines. 

Fat in such quantities as to float on the urine generally comes from 
the introduction of a catheter or from foreign admixture. Fatty 
degeneration of kidney, or leakage of a lymph vessel, or the opening 
of an abscess into the urinary tract may cause fat in the urine. It 
occurs as minute, highly refracting globules of various sizes (see a in 
Fig. 57). but sometimes, especially in chylous urine, in more intimate 



PART III. — THE URINE. 



141 



emulsion (as at b), the globules appearing under the microscope as 
mere specks. Fat may be recognized by its dissolving on addition 
of ether. 

Mucus and Pus. — Mucus is a normal constituent of urine. It is a 
transparent fluid, and would be invisible but for the mucus corpus- 
cles, epithelium and other sediments entangled in it. Though closely 
related to albumin, mucin is coagulated by acetic atcid and not by 
heat. Mucus is increased by irritation of the urinary tract, but as 
inflammation supervenes albumin appears and the urine is purulent. 
The mucus and pus corpuscles present the same appearance under the 
microscope as other leucocytes, viz. : rounded, colorless, very granu- 



Fig. 57. 



Fig. 58. 




Fat Globules. 



Pus Corpuscles. 



lar cells, a little larger than red blood corpuscles. (Fig. 58.) If the 
urine be greatly diluted, or, better, treated with acetic acid, the cells 
swell up, lose their granular appearance, become transparent, and 
show their nuclei {a in Fig. 58). The pus cell oftener than the mucus 
corpuscle has more than one nucleus. Pus may be distinguished from 
mucus: (1) It is always attended with albumin; (2) (Donne's test) 
treated with an alkali it forms a gelatinous mass ; (3) hydrogen per- 
oxide causes marked effervescence with pus. 

Epithelium in the urine may come from any part of the genito- 
urinary tract. The accompanying cut shows the typical forms of cells 
coming from various situations. It is generally impossible to locate 



142 



ESSENTIALS OF CHEMISTRY. 



the origin of an epithelial cell beyond the vagina and bladder, for 
their distinctive differences, but slight at best, are rendered still fainter 
by maceration in the urine. Renal epithelium comes from the urinifer- 
ous tubules, and are rounded and granular, and, unlike pus cells, they 
show their nuclei without acetic acid. They are usually associated 
with albumin and tube casts (Fig. 60), and therefore point to kidney 
disease. 
Tube Casts. — In hemorrhage from or inflammation of the kidney 




^-/ d 



(a) Epithelium from the human urethra ; {b) vagina; (c) prostate; (d) Cowper's glands ; 
(e) Littre's glands; (f) female urethra ; (£-) bladder. 



the urine usually contains microscopic casts or moulds of the urinifer- 
ous tubules formed by exudation into the tubule of coagulable 
material, which afterward contracts, becomes loose, and is washed 
out with the urine. As they imbed and bring away epithelial cells, 
granular matter, fat globules, blood disks, etc., they are a valuable 
index to the condition of the tubules. (1) Epithelial casts (see upper 
portion of figure) are those bearing renal epithelium. They indicate 



PART III. — THE URINE. 



H3 



desquamative nephritis, (2) Hyaline casts (shown in left-hand part 
of figure) are transparent and comparatively free from entangled 
material. They come from tubules whose epithelium is sound and 
adherent or from those bereft of epithelium. In the latter case they 
are more solid in appearance (waxy casts) and indicate serious 
nephritis. (3) Granular casts are opaque from presence of granular 
debris. (4) Fatty casts (see larger cast in figure) are such as carry 
oil globules, either free or contained in epithelial cells. They are 
proof of fatty degeneration of the kidney. (5) Blood casts contain 
blood corpuscles, and show that the haematuria is of renal origin. 
Spermatozoa occur in urine as a result of spermatorrhoea, noctur- 



Fig. 60. 



Fig. 61. 




Epithelial Cells and Tube Casts. 



Spermatozoa. 



nal emissions, or coitus. They are liable to escape observation, for 
they subside slowly, and are very small and transparent. Under a 
high power they are seen to consist of a small oval cell with a tail-like 
prolongation. Their tadpole-like appearance is shown in Fig. 61. 
They are motionless in urine, and remain for days unaltered. 

Microorganisms. — Urine being a solution of organic matters be- 
comes as soon as voided a ready medium for the growth of the lower 
forms of life, the germs of which get in from the air or unclean ves- 
sels. Besides various others we may mention: (1) Yeast fungus 
(shown on page 113) is seen during its sporule stage as transparent 
oval cells, sometimes arranging themselves in branches. It grows 
only in saccharine urine, though spores closely resembling it are seen 



144 



ESSENTIALS OF CHEMISTRY. 



in acid urine containing neither sugar nor albumin. (2) Sarcina is a 
fungus seldom found in urine, but more frequently in matters vomited 
during certain diseases of the stomach. The cells are arranged in 
cubes, resembling bales bound with cross-bands. The sarcina? shown 
at a in figure are from the urine, those at b from vomited matters. 

3. Bacteria {little rods). This is the general term given to the 
minute moving organisms invariably present in putrefying animal and 
vegetable matter. They consist of simple cells filled with a colorless 
fluid and presenting several varieties of form : (a) Micrococci appear- 

Fig. 62. 




d 

(a) Micrococci in short chains and groups; (&) sarcinse ; (c) fungi from acid fermentation ; 
(d) yeast cells from diabetic urine ; (e) mycelium of a fungus. 

ing as trembling points, distinguished from other particles by their 
progressive motion ; (b) Rods about the length of the diameter of blood 
disks, sometimes at rest, but usually vibrating across the field; (c) 
Vibriones, consisting of several rods joined together and moving with 
greater rapidity ; and (d) Zooglece, aggregations of bacteria held to- 
gether by gelatinous material and re'sembling masses of amorphous 
urates or phosphates. These various forms are shown in Fig. 41 and 42. 
Bacteria not only cause decomposition outside, but may set it up in 



PART III. — THE URINE. 145 

urine while yet within the bladder, provided they be introduced from 
without. This may be done by dirty catheters and sounds, or they 
may work their way down the urethra in the pus of a gleet. The 
ammoniacal fermentation thus set up soon induces cystitis. 

Extraneous bodies, such as hair, wool, or fragments of feathers, are 
often found in urinary deposits, and ludicrous mistakes have been 
made by observers not on their guard for such casual admixtures. 

Sediments. — The chemical examination of unorganized urinary 
sediments is generally an easy matter, for they usually consist of urates, 
phosphates, calcium oxalate, or uric acid. Warm the sediment with 
the supernatant urine, it dissolves — urates. If not, warm with acetic 
acid, it dissolves — phosphates. If not, warm with hydrochloric acid, 
it dissolves — calcium oxalate. If not, it is uric acid, which may be 
confirmed by the murexid test. 

Urinary Calguli. — Urinary calculi {calculus, a pebble) are com- 
posed of urinary sediments which have gathered around some nucleus 
(usually calcium oxalate or uric-acid crystals, or some foreign body) 
within the bladder, and being slowly deposited, particle upon particle 
and layer upon layer, the concretion becomes as hard as stone. The 
concretion often consists of successive layers of different sediments 
deposited during varying conditions of the urine. 

The qualitative analysis of calculi is easy. Saw the stone through 
the middle and see whether it be composed of the same material 
throughout or of successive layers of different sediments. If the 
former, take the sawdust ; if the latter, chip off a specimen from a 
single layer. But this should be pulverized very fine (for it is dissolved 
much less readily than fresh sediments), and then test by means of 
heat, acetic and hydrochloric acids, just as other sediments. 

The following method is easier in practice : — 

I. Heat to redness on a piece of platinum foil. If no residue, see 
II ; if a residue, see III. 

II. To a fresh portion apply the murexid test. If it responds it is 
ammonium urate or uric acid ; if it does not respond it is cystin or 
xanthin, see IV. 

III. To the residue, when cool, add hydrochloric acid. If it effer- 
vesces it is an oxalate or tirate, which may be determined by the 
murexid test ; if it does not effervesce it is a phosphate. 

IV. Dissolve some of the powder in nitric acid. If the solution is 
yellow it is xanthin ; if dark brown it is cystin. 



146 



ESSENTIALS OF CHEMISTRY. 



TABLE OF METRIC MEASURES. 



MEASURES OF LENGTH. 



Millimetre 

Centimetre 

Decimetre 

Metre 

Decametre 

Hectometre 

Kilometre 

Myriametre 



0.001 of a metre. 
0.010 of a metre. 
0.100 of a metre 
1. 000 Metre 
10.000 metres. 
100.000 metres. 
1000.000 metres 
10,000.000 metres 



= about 4 inches. 
— 39-37 inches. 



= about % of a mile. 
= about 63/3 miles. 



MEASURES OF SURFACE. 

Centiare = 1 Square metre = about i| square yards. 

Are = 100 Square metres. 

Hectare = io,oou Square metres = about 2^ acres. 



MEASURES OF VOLUME. 



Cubic centimetre = 

Litre (cubic decimetre) = 

Cubic metre = 

Cubic metre = 

Cubic metre = 



0.001 of a litre. 
1000. cubic centimetres. 
1000. cubic decimetres. 
1000. litres, or 1 kilolitre. 

1 stere. 



1 Milligramme 

1 Centigramme 

1 Decigramme 

1 Gramme* 

1 Decagramme 

1 Hectogramme 

1 Kilo(gramme) 

1 Tonneau 



MEASURES OF WEIGHT. 



0.001 of a gramme 
0.010 of a gramme. 
0.100 of a gramme. 
1. 000 Gramme 
10.000 grammes. 
100.000 grammes. 
1000.000 grammes 



= 1000. 



Kilos 



= about ^5 of a grain. 

= about 15% grains. 

= about -z\ lbs. 
= about 1 ton. 



INDEX. 



Absolute weight, 10 
Acetanilide, 117 
Acetic acid, 109 
Acetic aldehyde, 108 
Acid acetic, 109 

antimonic, 54 

antimonious, 54 

arsenic, 49, 50 

arsenious, 49, 50 

benzoic, 109 

boric or boracic, 76 

chloric, 33 

chlorous, 33 

chromic, 79 

citric, no 

cyanic, 61 

formic, no 

gallic, no 

hippuric, 1 40 

hydriodic, 31 

hydrobromic, 31 

hydrochloric, 31, 32 

hydrocyanic, 60 

hydroferricyanic, 61 

hydrofluoric, 31 

hydrosulphuric, 35 

hypochlorous, 33 

hyponitrous, 44 

lactic, no 

lithic (see Uric), 129 

malic, no 

meconic, 119 

muriatic, 31 

myronic, 115 

nitric, 45 

nitrohydrochloric, co 

nitromuriatic, 32 

nitrous, 45 

oleic, 107 

orthophosphoric, 48 

osmic, 93 

oxalic, no 

palmitic, 107 

perchloric, 33 

phosphoric, 49 

picric, no 

plumbic, 56 

prussic, 60 

pyrogallic, in 

pyrophosphoric, 48 

salicic, 56 

salicylic, in 



Acid, sodium phosphate, 123, 132 

stannic, 56 

stearic, 107 

succinic, in 

sulphocarbolic, 104 

sulphocyanic, 61 

sulphuric, 39 

sulphurous, 37 

tannic, in, 115 

tartaric, in 

uric, 129 

valerianic, 1 11 
Acid salts, 69 
Acids, definition of, 16, 22 

fatty, 107 

organic, 109 
Acidulous radical, 27 
Aconitine, 119 
Analytical table, 94, 95 
Affinity, chemical, 25 
Aging of liquors, 103 
Air, 41 

Albumin, 116, 133 
Alcohol, 101, 102 

amylic, 103 

ethylic, 102 

glycerylic, 104 

mannityl, 105 

methylic, 101 

phenylic, 104 

radicals, 101 

vinic, 102 

wood, 101 
Aldehydes, 101, 108 
Ale, 103 

Algaroth, powder of, 54 
Alkalies, metals of the, 65 
Alkaline earth metals, 71 
Alkaline group, 65 
Alkaloids, 118 
Alloys, 62 

Allotropic forms, 56 
Allylsulphocyanate, 115 
Aluminium, 76 

bronze, 76 

chloride, 76 

silicates, 77 

sulphate, 76 
Alum, 76 
Amalgam, 62 
Amides, 117 
Amines, 117 



147 



1 48 



INDEX. 



Ammonia, 42 
Ammoniac, 100 
Ammoniated mercury, 89 
Ammonio-chloride of mercury, 89 
Ammonio citrate of iron, 84 

ferric alum, 77 

magnesium phosphate, 72 

nitrate of silver, 52 

sulphate of copper, 52 

tartrate of iron, 84 
Ammonium, 66 

alum, 77 

amalgam, 66 

carbonate, 67 

hydrate, 66 

hydrosulphide, 67 

nitrate, 44 

nitrite, 41 
Amygdalin, 61, 115 
Amyl acetate, 104 

hydrate, 103 

nitrite, 106 
Amylic alcohol, 103 
Amy loses, 112 
Amylum, 112 
Analysis, 21 

acidulous radicals, 94 

definition of, 21 

metallic radicals, 94 
Aniline, 117 
Animal charcoal, 56 
Antidote, definition of, 51 
Antidotes to acids, 73 

to alkalies, 67 

to alkaloids, 118 

to antimony, 55 

to arsenic, 51 

to barium, 75 

to carbolic acid, 104 

to copper, 87 

to cyanides, 61 

to lead, 65 

to mercury, 90 

to oxalic acid, no 

to silver, 92 

to sulphuric acid, 40 
Antifebrin, 117 
Antimonious chloride, 54 

hydride, 54 

oxychloride, 54 

oxide, 54 

sulphide, 54 
Antimoniuretted hydrogen, 54 
Antimony, 53 

Antimony and potassium tartrate, 54 
Antimony, butter of, 54 
Antimonyl, 54 
Antipyrine, 118 
Antiseptics, 42 
Antizymotics, 42 
Apomorphine, 119 
Apparent weight, 10 
Aqua, 20 

ammonia, 66 

ammonise fortior, 66 

chlori, 29 

destillata, 23 

fortis, 45 



Arbutin, 116 
Argenti nitras, 91 
Argol, in 
Arsenic, 49, 50 

acid, 49, 50 

oxide, 50 

pentoxide, 50 

toxicology of, 50 

white, 50 
Arsenious acid, 49, 50 

hydride, 49 

iodide, 49 

sulphide, 49 
Arseniuretted hydrogen, 49 
Arsine, 49 

Artificial parchment, 112 
Asafoetida, 100 
Asbestos, 62 
Atmosphere, 41 
Atomic theory, 12 

weight, 13 
Atoms, 13 
Atropine, 119 
Auric chloride, 92 



Babbitt's metal, 54 
Bacteria, 120-144 
Baking powders, 70 
Balsam of Peru, 100 
Balsams, 100 
Barium, 75 

chromate, 75 
Bases, 22 

Basylous radicals, 27 
Beer, 103 
Beet sugar, 113 
Bengal light, 75 
Benzine, 98 
Benzoic acid, 109 
Benzoine, 100 
.Bichromates, 79 
Bile in urine, 138 
Bilirubin, 138 
Bismuth, 55 

ammonio-citrate, 55 

nitrate, 55 

oxynitrate, 55 

subcarbonate, 55 

subnitrate, 55 
Bismuthyl, 54 
Black lead, 56 

oxide of manganese, 
Bleaching, 24, 38, 74 

powder, 74 
Blood casts, 143 

in urine, 137 
Blue ointment, 87 

pill, 87 

vitriol, 85 
Bluestone, 85 
Boroglyceride, 76 - 
Borax, 76 
Boric acid, 76 
Boron, 76 
Brandy, 103 
Brass, 77 
Brimstone, 35 



INDEX. 



149 



Britannia, 54 
British gum, 113 
Bromides, test for, 30 
Bromine, 28 
Bromum, 28 
Bronze aluminium, 76 
Brucine, 119 
Butter of antimony, 54 
Butyl, 101 



Cadavarine, 120 
Cadmium, 79 
Caesium, 65, 71 
Caffeine, 119 
Calcium, 73 

carbonate, 73, 140 

chloride, 73 

hydrate, 73 

oxalate, 74, 140 

oxide, 73 

phosphate, 74 

sulphate, 74 
Calculi, urinary, 145 
Calomel, 88-89 
Calx, 73 

chlorata, 74 
Camphor, monobromated, 100 
Camphors, 100 
Cane sugar, 113 
Caoutchouc, 100 
Caramel, 103 
Carat fine, 92 
Carbamide, 117 
Carbazotic acid, no 
Carbolic acid, 104 
Carbohydrates, 112 
Carbon, 56 

dioxide, 57 

disulphide, 37 

group, 56 

monoxide, 57 
Carbonic acid, 56, 57 
Carburetted hydrogen, 99 
Casein, 116 
Catalysis, 18, 26, 105 
Caustic ammonia, 66 

potash, 70 
Cellulin, 112 
Celluloid, 112 
Cellulose, 112 
Centimeter, cubic, 147 
Cerium, 77 
Chalk, 73 
Charcoal, 56 

animal, 56 
Chemical action, 9 

affinity, 25 
Chemistry, definition of, 9 

inorganic, 15 

organic, 97 
Chinoline, 118 
Chloral, 108 

hydrate, 109 
Chloralum, 76 
Chloride of gold, 92 

of lime, 74 
Chlorides in urine, 132 



Chlorides, tests for, 132 
Chlorinated lime, 74 
Chlorine, 28 

group, 28 

oxides, 32 
Chloroform, 106 
Choke damp, 57 
Cholesterine, 108 
Choline, 120 
Chondrin, 116 
Chromates, 79 
Chrome yellow, 64 
Chromic acid, 79 
Chromium, 79 

trioxide, 79 
Cider, 103 

Cinchona alkaloids, 119 
Cinchonicine, 119 
Cinchonidine, 119 
Cinchonine, 119 
Cinnabar, 90 
Citric acid, no 
Citrine ointment, 88 
Classification of elements, 15 
Clay, 62 
Coal, 56 

mineral, 56 
Cobalt, 85 
Cocaine, 119 
Codeine, 119 
Coin, 91, 92 
Colchicine, 119 
Collodion, 112 
Colocynthin, 116 
Coloring matters, urinary, 130 
Combining weight, 13 
Combustible, 18 
Combustion, 18 

supporter of, 18 
Compounds, n 
Concentrated lye, 69 
Conine, 119 
Copal, 100 
Copper, 85 

ammonia-sulphate, 52 

arsenite, 52 

black oxide, 86 

group, 85 

suboxide, 86 
Copperas, 82 
Corals, 73 

Corrosive sublimate, 89 
Cotton, 112 
Crab orchard salts, 72 
Cream of tartar, 69 
Creasote, 105 
Creatine, 120 
Creatinine, 120 
Creta preparata, 73 
Crystallization, water of, 21 
Cupric hydrate, 86 

oxide, 86 

subacetate, 86 

sulphate, 85 
Cuprous oxide, 86 
Cyanates, 61 
Cyamic acid, 61 
Cyanide, mercuric, 60 



ISO 



INDEX. 



Cyanides, compound, 61 
Cyanogen, 60 
Cystin, 139 



Davy's method for urea, 127 
Decantation, 73 
Decay, 114 
Deliquesce, 21 
Deodorizers, 42 
Deposits, urinary, 145 
Dew point, 42 
Dextrin, 113 
Diabetic sugar, 114 

urine, 134 
Dialysis, 83 
Dialyzed iron, 83 
Dialyzer, 83 
Diamond, 56 
Diastase, 114 
Didymium, 75 
Diffusion, 60 

gases, 60 

liquids, 60 
Digitalin, 116 
Disinfectants, 42 
Distillation. 23 
Donne's test for pus, 141 
Donovan's solution, 49 
Doremus' method for urea, 128 
Drummond light, 17 
Dynamite, 104 



Earths, metals of the, 75 

Earthy phosphates, 122, 131, 133 

Effloresces, 21 

Elaterin, 116 

Electrolysis, 25 

Electro- positive and negative, 24 

Elements, 11 

classification of, 15 

groups of, 15 
Emplastrum plumbi, 63 
Emulsin, 115 
Epithelial casts, 142 
Epithelium, 141 
Epsom salts, 72 
Equation, 14 
Erbium, 75 

Esbach's albuminometer, 134 
Essential oils, 99 
Etching, 32 
Ether, 105 

chloric, 106 

hydrobromic, 106 

hydrochloric, 106 

nitrous, 106 

ozonized, 24 

sulphuric, 105 
Ethers, compound, 101, 105 

simple, 101, 105 
Ethyl bromide, 106 

aldehyde, 108 

chloride, 106 

hydrate, 102 

nitrite, 106 

oxide, 105 



Ethylic alcohol, 102 

Evaporation, 11 

Extraneous bodies in urine, 145 



Fat in urine, 140 
Fatty casts, 143 
Fats, 107 
Fehling's test, 135 

solution, 136 
Fermentation, acid, 123 

alkaline, 124 
Ferments, 114 
Ferri citras, 84 

carbonas saccharatus, 84 

et ammonii citras, 84 

et ammonii tartras, 84 

et potassii tartras, 84 

et quininae citras, 84 

et strychnia citras, 84 

pyrophosphas, 84 
Ferric chloride, 81 

hydrate, 83 

nitrate, 84 

sulphate, 82 
Ferricyanides, 61 
Ferricyanogen, 61 
Ferrocyanogen, 61 
Ferrous chloride, 82 

carbonate, 84 

hydrate, 83 

iodide, 84 

sulphate, 82 

sulphide, 84 
Ferrum redactum, 81 
Fibrin, 116 
Filtration, 73 
Fixed oils, 107 
Flint, 62 

Flowers of sulphur, 35 
Fluorides, tests for, 32 
Fluorine, 28 
Fluorspar, 28 
Fluxes, 81 
Flystone, 85 
Formic acid, no 
Formulae, 14 
Fowler's method for urea, 128 

solution, 50 
Fruit essences, artificial, 104 
Fungi, 122 
Fusel oil, 103 



Galena, 63 

Gallic acid, no 

Galls, oak, in 

Galvanized iron, 77 

Gas, definition of, 10 
illuminating, 57 
laughing, 44 
marsh, 99 

Gasoline, 98 

Gelatine, 116 

Gentianin, 116 

German silver, 85 

Germicides, 42 

Glass, 62 



INDEX. 



I5T 



Globulin, 116 
Glucose, 114, 134 
Glucosides, 115 
Glycerine, 104 
Glycerites, 104 
Glycyrrhizin, it6 
Glycerylic alcohol, 104 
Glycogen, 113 
Gold, 92 

leaf, 92 
Goulard's extract, 63 
Gramme, 147 
Granular casts, 143 
Grape sugar, 114 
Graphite, 56 
Gravity, specific, to 
Gray powder, 87 
Green fire, 75 
Green vitriol, 82 
Group, alkaline, 65 

alkaline earths, 71 

carbon, 56 

chlorine, 28 

copper, 85 

hydrogen and oxygen, 15 

iron, 79 

nitrogen, 40 

zinc, 77 
Guaiacol, 105 
Guaiacum, tincture, 138 
Gum resins, 100 
Gums, 113 
Gun cotton, 112 
Gutta percha, 100 
Gypsum, 74 



Haines' test, 136 
Hair dye, 11 1 
Hartshorn, 43 

spirits of, 43 
Homatropine, 119 
Homologous series, 98 
Hyaline casts, 143 
Hydracids, 31 
Hydrates, 22 
Hydrargyri — 

chloridum mite, 88 

cum creta, 87 

iodidum rubrum, 83 
viride, 88 

oxidum flavum, 89 
rubrum, 89 

subsulphas flavus, 88 
Hydrargyrum, 87 

cum creta, 87 
Hydrobromic ether, to6 
Hydrocarbons, 98 
Hydrochloric ether, 106 
Hydrocyanic acid, 60 
Hydro-ferricyanic acid, 61 
Hydro-ferrocyanic acid, 61 
Hydrogen, 16 

carburetted, 99 

cyanide, 60 

dioxide, 24 

oxide, 20 

peroxide, 20 



Hydragen sulphide, 35 
Hyoscyamine, 119 
Hydrometer, 10 
" Hypo," 33 
Hyponitrous acid, 44 
Hyposulphite of sodium, 38 
Hyposulphites, 38 

" ic," 27 

"ide," 33 



Ice, 20 

Ignis fatuus, 47 
Indestructibility, 9 
India rubber, 100 
Indican, 116, 130 
Ink, black, in 

indelible, 92 

sympathetic, 85 
Inorganic chemistry, 15 
Insolubility, influence of, 26 
Insoluble chlorides, 91 
Introduction, 9 
Iodide of nitrogen, 41 

of starch, 1 
Iodides, tests for, 32 
Iodine, 28 
Iodoform, 107 
Iridium, 93 
Iron, 81 

by hydrogen, 81 

cast, 81 

group, 79 

pig, 81 

reduced, 81 

salts (see Ferrous and Ferric), 81 

scale compounds of, 84 

wrought, 81 
Isologous series, 98 
Isomeric bodies, 99 
Isomerism, 98 

"ite" 33 



Jalapin, 116 
Javelle water, 71 



Kalium, 65 
Kaolin, 77 
Kerosene, 98 
Kreatine, 129 
Kreatinine, 129 

Labarraque's solution, 71 
Lac sulphuris, 35 
Lactic acid, no 
Lana philosophica, 78 
Lanolin, 108 
Lanthanum, 75 
Laughing gas, 44 
Lead, 63 

acetate, 63 

carbonate, 64 

chloride, 64 

chromate, 64 

dioxide, 63 



152 



INDEX. 



Lead, iodide, .64 

nitrate, 63 

oxide, 63 

plaster, 63 

puce, 63 

red, 63 

subacetate, 63 

sugar of, 63 

sulphate, 64 

sulphide, 64 

water, 63 

white, 64 
Ledoyen's disinfectant fluid, 63 
Leucin, 139 
Leucomai'nes, 120 
Lignin, 112 
Lime (see Calcium), 73 

chloride, 73 

kilns, 73 

quick, 73 

slaked, 73 

water, 73 
Limestone, 73 

magnesian, 71 
Linen, 112 
Linseed oil, 108 
Liquid, definition of, 10 
Liquor, 20-66 

acidi arseniosi, 50 

arsenii et hydrargyri iodidi, 49 

calcis, 73 

saccharatus, 73 

definition of, 20, 66 

ferri chloridi, 82 
nitratis, 84 
subsulphatis, 83 
tersulphatis, 83 

hydrargyri nitratis, 88 

iodi compositus, 30 

magnesii citratis, 72 

plumbi subacetatis, 63 

potassse, 70 

potassii arsenitis, 50 
Liter, 146 
Litharge, 63 
Lithium, 65 

urate, 65 
Litmus, 67, 125 
Lixiviation, 69 
Lubricating oil, 99 
Lugol's solution, 30 
Lunar caustic, 91 
Lustre, metallic, 62 
Lye, 69 



Magnesia, 72 

milk of, 72 
Magnesian fluid, 49 

limestone, 71 
Magnesium, 71 

carbonate, 72 

citrate, 72 

hydrate, 72 

oxide, 72 

phosphatis, 72 

sulphate, 72 
Malic acid, no 



Malt, 114 
Maltin, 114 
Manganates, 80 
Manganese, 80 

black oxide of, 80 

dioxide, 80 
Manganous sulphate, 80 

sulphide, 80 
Manna, 105 
Mannite, 105 
Mannityl alcohol, 105 
Marble, 73 
Marsh gas, 99 
Marsh's test, 52 
Mastic, 100 
Matter, 9 
Measures, 146 
Meerschaum, 71 
Menthol, 100 
Mercurial ointment, 87 
Mercuric ammonium chloride, 

chloride, 89 

cyanide, 60 

iodide, 88 

nitrate, 88 

oxide, 89 

sulphate, 88 

sulphide, 90 
Mercurous chloride, 88 

iodide, 88 

nitrate, 88 

oxide, 89 

sulphate, 88 

sulphide, 89 
Mercury, 87 

acid nitrate, 88 

ammoniated, 89 

bichloride, 89 

biniodide, 88 

black oxide, 89 

green iodide, 88 

mild chloride, 88 

oleate, 89 

proto-iodide, 88 

red iodide, 88 

red oxide, 89 

yellow oxide, 89 
Metallic lustre, 62 
Metals, 15, 62 
Metaphosphoric acid, 48 
Methane, 99 
Methyl hydrate, 101 
Methylated spirit, 102 
Methylic alcohol, 101 
Metric measures, 146 
Micrococci, 144 
Micrococcus urea, 124 
Microorganisms, 22, 114, 143 
Milk of magnesia, 72 

of sulphur, 35 

sugar, 114 
Millimeter, 146 
Mineral coal, 56 
Molecules, 13 
Molybdenum, 93 
Monobromated camphor, 100 
Monsel's solution, 83 
Morphine, 119 



INDEX. 



153 



Mother of vinegar, 114 
Mucilage of starch, 113 
Mucus, 122, 141 
Mulberry calculus, 140 
Murexid test, 130 
Muscarine, 120 
Mustard, 115 

Mycoderma aceti, 109, 114 
Myronic acid, 115 
Myrrh, 100 



Naphtha, 98 

Narceine, 119 

Narcotine, 119 

Nascent state, 26 

Natrium, 65 

Negative radicals, 27, 28 

Neuridine, 120 

Nitre, sweet spirits of, 106 

Nickel, 85 

Nicotine, 119 

Nitrates, tests for, 46 

Nitric acid, 45 

Nitric oxide, 45 

Nitrification, 45 

Nitrite of amyl, 106 

Nitrites, 45 

Nitro-cellulose, 112 

Nitrogen, 40 

dioxide, 45 

group, 40 

hydride, 42 

iodide of, 41 

monoxide, 44 

oxides, 44 

pentoxide, 45 

tetroxide, 45 

trioxide, 45 
Nitrogenous bodies, 116 
Nitro-glycerine, 104 
Nitrous acid, 45 

ether, 106 

oxide, 44 
Non-metals, 15 
Nux vomica alkaloids, 119 



Oi'dium albicans, 114 
Oil, fusel, 103 

linseed, 108 

of vitriol, 39 
Oils, essential, 99 

fixed, 107 

volatile, 99 
Oleic, 107 
Oleo-resins, 100 
Oleum terebinthinse, 99 
Opium alkaloids, 119 
Organic acids, X09 
Organic chemistry, 97 
Organized bodies, 97 
Orpiment, 49 
Orthophosphoric acid, 48 
Osmic acid, 93 
Osmium, 93 
" Ous/' 27 
Oxacids, 32 
11 



Oxalate of lime, 74 
Oxalic acid, no 
Oxidation, 18 
Oxide, definition of, 18 
Oxidizing agents, 19 
Oxychloride of antimony, 54 
Oxygen, 17 
Oxygenated water, 20 
Oxyhydrogen flame, 17 
Ozone, 19 

test for, 20 
Ozonized ether, 24 



Painters' colic, 65 
Pancreatin, 114 
Paper, 112 
Paraffine, 98 
Paraldehyde, 108 
Parchment, artificial, 1x2 
Paris green, 52 
Pavy's solution, 135 
Pearl ash, 69 

white, 55 
Pepsin, 114 
" Per," 33 
Perspiration, n 
Peru, balsam of, 100 
Petrolatum, 98 
Petroleum, 98 
Pewter, 55, 63 
Phenates, 104 
Phenacetine, 118 
Phenol, 104 
Phenyl alcohol, 104 

bisulphate, 105 
Phenylamine, 117 
Phosphates in urine, 131 
Phosphine, 47 

Phosphoretted hydrogen, 47 
Phosphoric acid, 49 
Phosphorus, 45 

hydride, 47 

oxides, 48 

pentoxide, 48 
Picric acid, no 

test for glucose, 136 
Physostigmine, 119 
Pilocarpine, 119 
Pilula hydrargyri, 87 
Plaster-of-Paris, 74 
Plasters, 108 
Platinic chloride, 71, 93 
Platinum, 92 
Plumbago, 56 
Plumbic acid, 56 
Plumbum, 63 

Poisoning by chloroform, 107 
Porcelain, 77 
Porter, 103 
Port wine, 103 
Potassium, 68 

acid carbonate, 69 

bromide, 70 

bicarbonate, 69 

bichromate, 79 

bitartrate, 69 

carbonate, 69 



154 



INDEX. 



Potassium chlorate, 17 

chromate, 79 

ferricyanide, 61 

ferrocyanide, 61 

hydrate, 70 

hypochlorite, 70 

iodate, 70 

iodide, 70 

manganate, 80 

permanganate, 80 

red chromate, 79 

sodium tartrate, 70 

sulpho-cyanate, 61 
Potato starch, 112 
Powder of Algaroth, 54 
Precedence of affinities, 25 
Precipitated chalk, 73 
Principles, proximate and ultimate, 100 
Propylamine, 117 
Propyl, 101 
Proteids, 116 
Proximate analysis, 100 

principles, 100 
Prussiate of potash, red, 61 

yellow, 61 
Prussic acid, 60 
Ptomaines, 119 
Ptyalin, 114 
Ptyalism, 90 
Purification of water, 23 
Pus in urine, 141 
Putrefaction, 114 
Putrescine, 120 
Pyroligneous, 101 
Pyrogallic acid, iit* 1 
Pyrophosphoric acid, 48 



Quantivalence, 26 
Quevenne's iron, 8 
Quicklime, 73 
Quicksilver, 87 
Quinicine, 119 
Quinidine, 119 
Quinine, 119 
Quinoidine, 119 



Radicals, definition of, 24 

basylous, 27 

negative, 24 

positive, 27 

the alcohol, 101 
Rancidity of fats, ic8 
Ratsbane, 50 
Realgar, 49 
Red fire, 75 

Red prussiate of potash, 61 
Reduced iron, 81 
Reinsch's test, 52 
Resina, 99 
Resins, 99 
Resorcin, 105 
Respiration, 19 
Rex magnus, 76 
Rhigoline, 99 
Rochelle salt, 70 



Rock crystal, 62 
Roll sulphur, 00 
Rosin (see Resin), 99 
Rubidium, 65, 71 



Saccharoses, 113 
Salicylic acid, 11 1 
Salicin, 115 
Salivation, 90 
Salt, common, 31 
Salts, acid, 69 

" bi," 69 

crab orchard, 72 

Epsom, 72 

normal, 69 

of tartar, 69 
Sal volatile, 67 
Samarium, 75 
Sand, 62 
Santonin, 116 
Saponification, 108 
Saponin, 116 
Sarcina, 144 

Scale compounds of iron, 
Scandium, 75 
Scheele's green, 52 
Secretion of urine, 121 
Sediments, urinary, 145 
Selenium, 34 
Sewer gas, 35 
Shellac, 100 
Sherry wine, 103 
Silicates, 62 
Silicic acid, 56, 62 
Silicic oxide, 62 
Silicon, 61 
Silver, 91 

action of light on, 92 

ammonio-nitrate, 52 

arsenite, 52 

bromide, 92 

chloride, 91 

cyanide, 91 

german, 85 

group, 91 

iodide, 92 

nitrate, 91 

oxide, 91 
Slaked lime, 73 
Soaps, 108 
Soapstone, 62 
Soda water, 58 
Sodio-ammonium, 66 
Sodio-potassium tartrate, 70 
Sodium, 67 

amalgam, 66 

borate, 76 

chloride, 67 

hypochlorite, 71 

hyposulphite, 38 

salicylate, 11 1 

sulphocarbolate, 105 
Solder, 63 

Solid, definition of, 10 
Solanin, 116 
Soluble glass, 62 
Solution, Donovan's, 49 



INDEX. 



155 



Solution, Labarraque's, 71 

rationale of, 21 
Spasmotoxinc, 120 
Specific gravity, 10 
flask, 10 

weight, 10 
Spectroscope, 138 
Spermatozoa, 143 
Spirit, methylated, 102 

pyroligneous, 101 
Spirits, 66 

of hartshorn, 43 

of wine, 102 
Spiritus setheris nitrosi, 106 

ammonise, 66 

ammonise aromaticus, 66 

frumenti, 103 

vini gallici, 103 
Stannic acid, 56 

salts, 63 
Stannous salts, 63 
Stannum, 56 
Starch, 112 
Steam, 20 
Steel, 81 

Stereotyping metal, 55 
Stibine, 54 
Stibium, 53 
Strontium, 75 
Strychnine, 119 
Styptic collodion, 112 
Sublimation, 23 
Sublimed sulphur, 35 
Succinic acid, 111 
Sugar, beet, 113 

cane, 113 

diabetic, 114 

grape, 114 

in urine, 134 

milk, 114 

of lead, 63 
Sulphates, tests for, 133 
Sulphites, 38 
Sulpho-cyanates, 61 
Sulphur, 35 

dioxide, 37 

lotum, 35 

precipitatum, 35 

sublimatum, 35 

peroxide, 38 
Sulphuretted hydrogen, 35 
Sulphuric acid, 39 

ether, 105 
Supporter of combustion, 18 
Symbols, 13 
Sympathetic ink, 85 
Synaptase, 115 
Synthesis, 21 
Syrupus calcii lacto-phosphatis, 74 

scillae comp., 54 

simplex, 114 



Table, analytical, for metals, 94 

analytical, for negative radicals, 95 

of elements, 12 

of metric measure, 146 

of solubilities, 96 



Table of valences,»27 
Tannic acid, in 
Tannin, in, 115 
Tartar, cream of, 69 

emetic, 54 
Tartaric acid, in 
Tellurium, 34 

Temperature, influence of, 25 
Terebene, 99 
Terminations, 27 
Tersulphate of iron, 82 
Tests, acidity, 67 

acidulous radicals, 95 

alcohol, 102 

alkali metals, 71 

alkaline earth metals, 75 

alkalinity, 67 

ammonia, 44 

ammonium salts, 67 

antimony, 55 

arsenic, 51 

barium, 75 

bile, 138 

bile acids, 139 

bismuth, 55 

blood, 137 

boron, 76 

bromide, 32 

bromine, 32 

brucine, 119 

cadmium, 79 

calcium, 75 

carbonates, 59 

carbon dioxide, 59 

carbonic acid, 59 

chlorides, 32 

chlorine, 32 

chloroform, 107 

chromates, 80 

cobalt, 85 

coloring matters, urinary, 130 

copper, 86 

cyanides, 61 

fats, 140 

fluorides, 32 

fluorine, 32 

gallic acid, no 

glucose in urine, 134 

hard water, 22 

heat, for albumen, 133 

hydrocyanic acid, 61 

hydrogen sulphide, 36 

iodides, 32 

iodoform, 107 

iodine, 32 

iron, 84 

lead, 64 

lithium, 66 

magnesian, 75 

manganese, 80 

Marsh's, 52-55 

mercury, 90 

metallic radical, 94 

morphine, 119 

murexid, 130 

nickel, 85 

nitrates, 46 

nitric acid, 46 



1 5 6 



INDEX. 



Tests, nitrogenous bodies, 116 

organic matter in water, 23 

oxalic acid, 111 

oxygen, 18, 45 

ozone, 19 

phosphates, 133 

phosphoric acid, 49 

phosphorus, 47 

potassium, 71 

pus, 141 

pyrogallic acid, 11 1 

quinine, 119 

Reinsch's, 52 

salicylic acid, 111 

silver, 92 

sodium, 68 

starch, 113 

strychnine, 119 

strontium, 75 

sugar, 134 

sulphates, 40, 133 

sulphuric acid, 39 

tannic acid, in 

urates, 129 

urea, 127 

uric acid, 130 

urinary calculi, 145 

urinary sediments, 145 

water in alcohol, 85 

zinc, 78 
Tetanine, 120 
Tetanotoxine, 120 
Theine, 119 
Theory, atomic, 12 
Thrush, 114 
Tin, 62 
Tinct. ferri chloridi, 85 

iodi, 30 
Tinctures, 66 
Tin foil, 62 
Tolu, 100 

Torula cerevisiae, 114 
Toxicology of arsenic, 50 
Trichloraldehyde, 108 
Trichlormethane, 106 
Trimethylamine, 117 
Triple phosphate, 131 
Trommer's test, 135 
Trypsin, 114 
Tube casts, 142 
Turpene, 99 
Turpentine, 99 
Turpeth mineral, 88 
Type metal, 63 
Typhotoxine, 120 
Tyrotoxine, 120 
Ty rosin, 139 

Ultimate analysis, 100 

principals, 100 
Unguentum antimonii, 54 

hydrargyri, 87 
nitratis, 88 
Urates, 122, 130, 133 
Urea, 117, 119, 126 

estimation of, 127 

nitrate, 127 



Urea, quantitative analysis, 127 

tests for, 127 
Uric acid, 129 
Urinary calculi, 145 

sediments, 145 
Urine, T21 

acid fermentation, 123 

alkaline fermentation, 124 

chemical constituents, 126 

color, 123 

coloring matters, 130 

fluidity, 122 

normal, 122 

odor, 123 

opacity, 122 

physical properties, 122 

quantity, 122 

reaction, 123 

specific gravity, 125 

transparency, 122 
Urinometer, 125 
Urobilin, 130 
Urohsematin, 130 
Uroindican, 130 
Uroxanthin, 130 



Valence, 26 
Valerian, in 
Valerianic acid, in 
Vaseline, 99 
Veratrine, 119 
Ventilation, 59 
Verdigris, 86 
Vermilion, 90 
Vibriones, 145 
Vinegar, 109 
Vinum antimonii, 54 

rubrum, 103 

xericum, 103 
Vitellin, 116 
Vitriol, blue, 85 

green, 82 

oil of, 39 

white, 78 
Volatile oils, 99 
Volatility, influence of, 25 
Vulcanized rubber, 100 



Water, 20 

alkaline, 24 
chalybeate, 24 
carbonated, 23 
distilled, 23 
drinkable, 22 
gas, 20 
hard, 22, 74 
impure, test for, 23 
mineral, 23 
natural, 22 
of crystallization, 21 
oxygenated, 20 
potable, 22 
purification of, 23 
saline, 24 
sulphur, 24 
thermal, 24 






Water-glass, 62 
Waxy casts, 143 
Weight, o 

absolute, 10 

apparent, 10 
Weights, atomic, 13 

combining, 13 

specific, 10 
White arsenic, 50 

lead, 64 

precipitate, 89 

vitriol, 78 
Whisky, 103 
" Will-o'-the-wisp," 
Wines, 103 
Wood alcohol, 101 

naphtha, 101 

spirit, 101 
Woody fibre, 112 



47 



INDEX. 

Xanthin, 120, 145 



Yeast, 114 

fungus, 143 
Yellow chrome, 64 

prussiate of potash, 61 
Ytterbium, 75 
Yttrium, 75 



Zinc, 77 

carbonate, 78 
chloride, 78 
oxide, 78 
sulphate, 78 
sulphide, 78 
white, 78 

Zooglese, 144 



157 



CATALOGUE No. 7. 



JULY, 1890. 



A CATALOGUE 

OF 

Books for Students. 

INCLUDING THE 

PQUIZ-COMPENDS? 



CONTENTS. 



New Series of Manuals, 2, 

Anatomy, 

Biology, 

Chemistry, . 

Children's Diseases 

Dentistry, 

Dictionaries, 

Eye Diseases, 

Electricity, . 

Gynaecology, 

Hygiene, 

Materia Medica_ 

Medical Jurisprudence, 



3,4,5 
6 



PAGK 

Obstetrics. . 

Pathology, Histology 

Pharmacy, . 

Physiology, . 

Practice of" Medicine, 

Prescription Books, 

PQuiz-Compends ? 

Skin Diseases, 

Surgery, 

Therapeutics, 

Urine and Urinary Organs 

Venereal Diseases, . . 13, 



*4 



T -5 



PUBLISHED BY 



P. BLAKISTON, SON & CO., 

Medical Booksellers, Importers and Publishers, 

LARGE STOCK OF ALL STUDENTS' BOOKS, AT 
THE LOWEST PRICES. 

1012 Walnut Street, Philadelphia. 



*#* For sale by all Booksellers, or any book will be sent by mail, 
postpaid, upon receipt of price. Catalogues of books on all branches 
of Medicine, Dentistry, Pharmacy, etc., supplied upon application. 

Xgjr' Gould's New Medical Dictionary Just Ready. See page ib. 



"An excellent Series of Manuals." — Archives of Gynecology. 

A NEW SERIES OF 

STUDENTS' MANUALS 

On the various Branches of Medicine and Surgery. 

Can be used by Students of any College. 

Price of each, Handsome Cloth, $3.00. Full Leather, $3.50. 

The object of this series is to furnish good manuals 
for the medical student, that will strike the medium 
between the compend on one hand and the prolix text- 
book on the other — to contain all that is necessary for 
the student, without embarrassing him with a flood of 
theory and involved statements. They have been pre- 
pared by well-known men, who have had large experience 
as teachers and writers, and who are, therefore, well 
informed as to the needs of the student. 

Their mechanical execution is of the best — good type 
and paper, handsomely illustrated whenever illustrations 
are of use, and strongly bound in uniform style. 

Each book is sold separately at a remarkably low 
price, and the immediate success of several of the 
volumes shows that the series has met with popular 
favor. ■ 

No. 1. SURGERY. 236 Illustrations. . 

A Manual of the Practice of Surgery. By Wm. J. 

Walsham, M.D., Asst. Surg, to, and Demonstrator of 

Surg, in, St. Bartholomew's Hospital, London, etc. 

228 Illustrations. 

Presents the introductory facts in Surgery in clear, precise 
language, and contains all the latest advances in Pathology, 
Antiseptics, etc. 

" It aims to occupy a position midway between the pretentious 
manual and the cumbersome System of Surgery, and its general 
character may be summed up in one word — practical." — The Medi- 
cal Bulletin. 

"Walsham, besides being an excellent surgeon, is a teacker in 
its best sense, and having had very great experience in the 
preparation of candidates for examination, and their subsequent 
professional career, may be relied upon to have carried out his 
work successfully. Without following out in detail his arrange- 
ment, which is excellent, we can at once say that his book is an 
embodiment of modern ideas neatly strung together, with an amount 
of careful organization well suited to the candidate, and, indeed, to 
the practitioner." — British Medical Journal. 

Price of each Book, Cloth, $3.00 ; Leather, $3.50. 



THE NEW SERIES OF MANUALS. 



No. 2. DISEASES OF -WOMEN. 150 Illus. 

NEW EDITION. 

The Diseases of Women. Including Diseases of the 
Bladder and Urethra. By Dr. F. Winckel, Professor 
of Gynaecology and Director of the Royal University 
Clinic for Women, in Munich. Second Edition. Re- 
vised and Edited by Theophilus Parvin, m.d., 
Professor of Obstetrics and Diseases of Women and 
Children in Jefferson Medical College. 150 Engrav- 
ings, most of which are original. 
'* The book will be a valuable one to physicians, and a safe and 

satisfactory one to put into the hands of students. It is issued in a 

neat and attractive form, and at a very reasonable price." — Boston 

Medical and Surgical Journal. 

No. 3. OBSTETRICS. 227 Illustrations. 
A Manual of Midwifery. By Alfred Lewis Galabin, 
M.A., M.D., Obstetric Physician and Lecturer on Mid- 
wifery and the Diseases of Women at Guy's Hospital, 
London; Examiner in Midwifery to the Conjoint 
Examining Board of England, etc. With 227 Illus. 
" This manual is one we can strongly recommend to all who 
desire to study the science as well as the practice of midwifery. 
Students at the present time not only are expected to know the 
principles of diagnosis, and the treatment of the various emergen- 
cies and complications that occur in the practice of midwifery, but 
find that the tendency is for examiners to ask more questions 
relating to the science of the subject than was the custom a few 
years ago. * * * The general standard of the manual is high ; 
and wherever the science and practice of midwifery are well taught 
it will be regarded as one of the most important text-books on the 
subj ect.' ' — London Practitioner. 

No. 4. PHYSIOLOGY. Fourth Edition. 

321 ILLUSTRATIONS AND A GLOSSARY. 

A Manual of Physiology. By Gerald F. Yeo, m.d., 
F.R.C.S., Professor of Physiology in King's College, 
London. 321 Illustrations and a Glossary of Terms. 
Fourth American from second English Edition, revised 
and improved. 758 pages. 

This volume was specially prepared to furnish students with a 
new text-book of Physiology, elementary so far as to avoid theories 
which have not borne the test of time and such details of methods 
as are unnecessary for students in our medical colleges. 

" The brief examination I have given it was so favorable that I 
placed it in the list of text-books recommended in the circular of the 
University Medical College." — Prof. Lewis A. Stimson, m.d., 
37 East 33d Street, New York. 

Price of each Book, Cloth, $3.00; Leather, $3.50. 



THE NEW SERIES OF MANUALS. * 



No. 5. ORGANIC CHEMISTRY. 

Or the Chemistry of the Carbon Compounds. By Prof. 
Victor von Richter, University of Breslau. Au- 
thorized translation, from the Fourth German Edition. 
By Edgar F. Smith, m.a., ph.d. ; Prof, of Chemistry 
in University of Pennsylvania; Member of the Chem. 
Socs. of Berlin and Paris. 

" I must say that this standard treatise is here presented in a 
remarkably compendious shape."— y. W. Holland, m.d., Professor 
of Chemistry , Jefferson Medical College, Philadelphia. 

** This work brings the whole matter, in simple, plain language, 
to the student in a clear, comprehensive manner. The whole 
method of the work is one that is more readily grasped than that of 
older and more famed text-books, and we look forward to the time 
when, to a great extent, this work will supersede others, on the 
score of its better adaptation to the wants of both teacher and 
student/' — Pharmaceutical Record. 

11 Prof, von Richter's work has the merit of being singularly- 
clear, well arranged, and for its bulk, comprehensive. Hence, it 
will, as we find it intimated in the preface, prove useful not merely 
as a text-book, but as a manual of reference." — The Chemical 
News, London. 

No. 6. DISEASES OP CHILDREN. 

SECOND EDITION. 

A Manual. By J. F. Goodhart, m.d., Phys. to the 
Evelina Hospital for Children ; Asst. Phys. to 
Guy's Hospital, London. Second American Edition. 
Edited and Rearranged by Louis Starr, m.d., Clinical 
Prof, of Dis. of Children in the Hospital of the Univ. 
of Pennsylvania, and Physician to the Children's Hos- 
pital, Phila. Containing many new Prescriptions, a list 
of over 50 Formulae, conforming to the U. S. Pharma- 
copoeia, and Directions for making Artificial Human 
Milk, for the Artificial Digestion of Milk, etc. Illus. 

" The author has avoided the not uncommon error of writing a 
book on general medicine and labeling it ' Diseases of Children/ 
but has steadily kept in view the diseases which seemed to be 
incidental to childhood, or such points in disease as appear to be so 
peculiar to or pronounced in children as to justify insistence upon 
them. * * * A safe and reliable guide, and in many ways 
admirably adapted to the wants of the student and practitioner." — 
American Journal of Medical Science. 

Price of each Book, Cloth, $3.00 ; Leather, $3.50. 



THE NEW SERIES OF MANUALS. 



No. 6. Goodhart and Starr : — Continued. 

" Thoroughly individual, original and earnest, the work evi- 
dently of a close observer and an independent thinker, this book, 
though small, as a handbook or compendium is by no means made 
up of bare outlines or standard facts." — The Therapeutic Ga- 
zette. 

" As it is said of some men, so it might be said of some books, 
that they are 'born to greatness/ This new volume has, we 
believe, a mission, particularly in the hands of the younger 
members of the profession. In these days of prolixity in medical 
literature, it is refreshing to meet with an author who knows both 
what to say and when he has said it. The work of Dr. Goodhart 
(admirably conformed, by Dr. Starr, to meet American require- 
ments) is the nearest approach to clinical teaching without the 
actual presence of clinical material that we have yet seen." — New 
York Medical Record. 

No. 7. PRACTICAL THERAPEUTICS. 

FOURTH EDITION, WITH AN INDEX OF DISEASES. 

Practical Therapeutics, considered with reference to 
Articles of the Materia Medica. Containing, also, an 
Index of Diseases, with a list of the Medicines 
applicable as Remedies. By Edward John Waring, 
m.d., f.r.c.p. Fourth Edition. Rewritten and Re- 
vised by Dudley W. Buxton, m.d., Asst. to the Prof, 
of Medicine at University College Hospital. 

" We wish a copy could be put in the hands of every Student or 
Practitioner in the country. In our estimation, it is the best book 
of the kind ever written."— N. Y. Medical Journal. 

No. 3. MEDICAL JURISPRUDENCE AND 
TOXICOLOGY. 

NEW, REVISED AND ENLARGED EDITION. 

By John J. Reese, m.d., Professor of Medical Jurispru- 
dence and Toxicology in the University of Pennsyl- 
vania ; President of the Medical Jurisprudence Society 
of Phila. ; 2d Edition, Revised and Enlarged. 

" This admirable text-book." — Amer.Jour. of Med. Sciences. 

u We lay this volume aside, after a careful perusal of its pages, 
with the profound impression that it should be in the hands of every 

doctor and lawyer. It fully meets the wants of all students 

He has succeeded in admirably condensing into a handy volume all 
the essential points." — Cincinnati Lancet and Clinic. 

Price of each Book, Cloth, $3,00; Leather, $3.50. 



6 STUDENTS' TEXT-BOOKS AND MANUALS. 

ANATOMY. 

Macalister's Human Anatomy: 816 Illustrations. A new 
Text-book for Students and Practitioners, Systematic and Topo- 
graphical, including the Embryology, Histology and Morphology 
of Man. With special reference to the requirements of 
Practical Surgery and Medicine. With 816 Illustrations, 
400 of which are original. Octavo. Cloth, 7.50; Leather, 8.50 

Ballou's Veterinary Anatomy and Physiology. Illustrated. 
By Wm. R. Ballou, m.d., Professor of Equine Anatomy at New 
York College of Veterinary Surgeons. 29 graphic Illustrations. 
i2mo. Cloth, 1. 00 ; Interleaved for notes, 1.25 

Holden's Anatomy. A manual of Dissection of the Human 
Body. Fifth Edition. Enlarged, with Marginal References and 
over 200 Illustrations. Octavo. Cloth, 5.00; Leather, 6.00 

Bound in Oilcloth, for the Dissecting Room, $4.50. 

" No student of Anatomy can take up this book without being 
pleased and instructed. Its Diagrams are original, striking and 
suggestive, giving more at a glance than pages of text description. 
* * * Xhe text matches the illustrations in directness of prac- 
tical application and clearness of detail." — Nezv York Medical 
Record. 

Holden's Human Osteology. Comprising a Description of the 
Bones, with Colored Delineations of the Attachments of the 
Muscles. The General and Microscopical Structure of Bone and 
its Development. With Lithographic Plates and Numerous Illus- 
trations. Seventh Edition. 8vo. Cloth, 6.00 

Holden's Landmarks, Medical and Surgical. 4th ed. Clo., 1.25 

Heath's Practical Anatomy. Sixth London Edition. 24 Col- 
ored Plates, and nearly 300 other Illustrations. Cloth, 5.00 

Potter's Compend of Anatomy. Fourth Edition. 117 Illus- 
trations. Cloth, 1. 00; Interleaved for Notes, 1.25 

CHEMISTRY. 

Bartley's Medical Chemistry. Second Edition. A text-book 
prepared specially for Medical, Pharmaceutical and Dental Stu- 
dents. With 50 Illustrations, Plate of Absorption Spectra and 
Glossary of Chemical Terms. Revised and Enlarged. Cloth, 2.50 

Trimble. Practical and Analytical Chemistry. A Course in 
Chemical Analysis, by Henry Trimble, Prof, of Analytical Chem- 
istry in the Phila. College of Pharmacy. Illustrated. Third 
Edition. 8vo. Cloth, 1.50 

J$S" See pages 2 to 5 for list of Students' Manuals. 



STUDENTS' TEXT-BOOKS AND MANUALS. 7 

Chemistry : — Continued. 

Bloxam's Chemistry, Inorganic and Organic, with Experiments. 
Seventh Edition. Enlarged and Rewritten. 330 Illustrations. 

Cloth, 4.50; Leather, 5.50 

Richter's Inorganic Chemistry. A text-book for Students. 
Third American, from Fifth German Edition. Translated by 
Prof. Edgar F. Smith, ph.d. 89 Wood Engravings and Colored 
Plate of Spectra. Cloth, 2.00 

Richter's Organic Chemistry, or Chemistry of the Carbon 
Compounds. Illustrated. Cloth, 3.00; Leather, 3.50 

Symonds. Manual of Chemistry, for the special use of Medi- 
cal Students. By Brandreth Symonds, a.m., m.d., Asst. 
Physician Roosevelt Hospital, Out-Patient Department; Attend- 
ing Physician Northwestern Dispensary, New York. i2mo. 

Cloth, 2.00; Interleaved for Notes, 2.40 

Tidy. Modern Chemistry. 2d Ed. Cloth, 5.50 

Leffmann's Compend of Chemistry. Inorganic and Organic. 
Including Urinary Analysis and the Sanitary Examination of 
Water. New Edition. Cloth, 1.00; Interleaved for Notes, 1.25 

Muter. Practical and Analytical Chemistry. Second Edi- 
tion. Revised and Illustrated. Cloth, 2.00 

Holland. The Urine, Common Poisons, and Milk Analysis, 
Chemical and Microscopical. For Laboratory Use. 3d 
Edition, Enlarged. Illustrated. Cloth, 1.00 

Van Niiys. Urine Analysis. Ulus. Cloth, 2.00 

Wolff's Applied Medical Chemistry. By Lawrence Wolff, 
M.D.,Dem. of Chemistry in Jefferson Medical College. Clo.,1.00 

CHILDREN. 

Goodhart and Starr. The Diseases of Children. Second 
Edition. By J. F. Goodhart, m.d., Physician to the Evelina 
Hospital for Children ; Assistant Physician to Guy's Hospital, 
London. Revised and Edited by Louis Starr, m.d., Clinical 
Professor of Diseases of Children in the Hospital of the Univer- 
sity of Pennsylvania; Physician to the Children's Hospital, 
Philadelphia. Containing many Prescriptions and Formulae, 
conforming to the U. S. Pharmacopoeia, Directions for making 
Artificial Human Milk, for the Artificial Digestion of Milk, etc. 
Illustrated. Cloth, 3.00; Leather, 3.50 

Hatfield. Diseases of Children. By M. P. Hatfield, m.d., 
Professor of Diseases of Children, Chicago Medical College. 
i2mo. . Cloth, 1. 00; Interleaved, 1.25 

Day. On Children. A Practical and Systematic Treatise. 
Second Edition. 8vo. 752 pages. Cloth, 3.00; Leather, 4.00 

j&SP 5 - See pages 14 and 13 for list of ? Quiz- Compends ? 



8 STUDENTS' TEXT-BOOKS AND MANUALS. 

Children: — Continued. 

Meigs and Pepper. The Diseases of Children. Seventh 
Edition. 8vo. Cloth, 5.00; Leather, 6.00 

Starr. Diseases of the Digestive Organs in Infancy and 
Childhood. With chapters on the Investigation of Disease, 
and on the General Management of Children. By Louis Starr, 
m.d., Clinical Professor of Diseases of Children in the Univer- 
sity of Pennsylvania; with a section on Feeding, including special 
Diet Lists, etc. Illus. Cloth, 2.50 

DENTISTRY. 

Fillebrown. Operative Dentistry. 330 Illus. Cloth, 2.50 

Flagg's Plastics and Plastic Filling. 3d Ed. Preparing. 

Gorgas. Dental Medicine. A Manual of Materia Medica and 
Therapeutics. Third Edition. Cloth, 3.50 

Harris. Principles and Practice of Dentistry. Including 
Anatomy, Physiology, Pathology, Therapeutics, Dental Surgery 
and Mechanism. Twelfth Edition. Revised and enlarged by 
Professor Gorgas. 1028 Illustrations. Cloth, 7.00 ; Leather, 8.00 

Richardson's Mechanical Dentistry. Fifth Edition. 569 
Illustrations. 8vo. Cloth, 4.50; Leather, 5.50 

Stocken's Dental Materia Medica. Third Edition. Cloth, 2.50 

Taft's Operative Dentistry. Dental Students and Practitioners. 
Fourth Edition. 100 Illustrations. Cloth, 4.25 ; Leather, 5.00 

Talbot. Irregularities of the Teeth, and their Treatment. 
Illustrated. 8vo. Cloth, 1.50 

Tomes' Dental Anatomy. Third Ed. 191 Illus. Cloth, 4.00 

Tomes' Dental Surgery. 3d Edition. Revised. 292 Illus. 
772 Pages. Cloth, 5.00 

DICTIONARIES. 

Gould's New Medical Dictionary. Containing the Definition 
and Pronunciation of all words in Medicine, with many useful 
Tables etc. y 2 Dark Leather, 3.25 ; ^ Mor., Thumb Index 4.25 
See last page. 

Cleaveland's Pocket Medical Lexicon. 31st Edition. Giving 

correct Pronunciation and Definition. Very small pocket size. 

Cloth, red edges .75 ; pocket-book style, 1.00 

LrOngley's Pocket Dictionary. The Student's Medical Lexicon, 
giving Definition and Pronunciation of all Terms used in Medi- 
cine, with an Appendix giving Poisons and Their Antidotes, 
Abbreviations used in Prescriptions, Metric Scale of Doses, etc. 
24mo. Cloth, 1. 00; pocket-book style, 1.25 

J£g^ See pages 2 to $ for list 0/ Students' Manuals. 



STUDENTS' TEXT-BOOKS AND MANUALS. 9 

EYE. 

Arlt. Diseases of the Eye. Including those of the Conjunc- 
tiva, Cornea, Sclerotic, Iris and Ciliary Body. By Prof. Von 
Arlt. Translated by Dr. Lyman Ware. Illus. 8vo. Cloth, 2.50 

Hartridge on Refraction. 4th Ed. Cloth, 2.00 

Meyer. Diseases of the Eye. A complete Manual for Stu- 
dents and Physicians. 270 Illustrations and two Colored Plates. 
8vo. Cloth, 4.50; Leather, 5.50 

Fox and Gould. Compend of Diseases of the Eye and 
Refraction. 2d Ed. Enlarged. 71 Illus. 39 Formulae. 

Cloth, 1. 00; Interleaved for Notes, 1.25 

ELECTRICITY. 

Mason's Compend of Medical and Surgical Electricity. 

With numerous Illustrations. i2mo. Cloth, 1.00 

HYGIENE. 

Parkes' (Ed. A.) Practical Hygiene. Seventh Edition, en- 
larged. Illustrated. 8vo. Cloth, 4.50 

Parkes' (L. C.) Manual of Hygiene and Public Health. 
i2mo. Cloth, 2.50 

Wilson's Handbook of Hygiene and Sanitary Science. 
Sixth Edition. Revised and Illustrated. Cloth, 2.75 

MATERIA MEDICA AND THERAPEUTICS. 

Potter's Compend of Materia Medica, Therapeutics and 

Prescription Writing. Fifth Edition, revised and improved. 

Cloth, 1.00; Interleaved for Notes, 1.25 

Biddle's Materia Medica. Eleventh Edition. By the late 
John B. Biddle, m.d., Professor of Materia Medica in Jefferson 
Medical College, Philadelphia. Revised, and rewritten, by 
Clement Biddle, m.d., Assist. Surgeon, U. S. N., assisted by 
Henry Morris, m.d. 8vo., illustrated. Cloth, 4.25; Leather, 5.00 

Headland's Action of Medicines. 9th Ed. 8vo. Cloth, 3.00 

Potter. Materia Medica, Pharmacy and Therapeutics. 
Including Action of Medicines, Special Therapeutics, Pharma- 
cology, etc. Second Edition. Cloth, 4.00; Leather, 5,00 

Starr, Walker and Powell. Synopsis of Physiological 
Action of Medicines, based upon Prof. H. C. Wood's " Materia 
Medica and Therapeutics." 3d Ed. Enlarged. Cloth, .75 

Waring. Therapeutics. With an Index of Diseases and 
Remedies. 4th Edition. Revised. Cloth, 3.00; Leather, 3.50 
/£&=" See pages 14 and 13 for list of ? Quiz- Compends ? 



10 STUDENTS' TEXT-BOOKS AND MANUALS. 

MEDICAL JURISPRUDENCE. 

Reese. A Text-book of Medical Jurisprudence and Toxi- 
cology. By John J. Reese, m.d., Professor of Medical Juris- 
prudence and Toxicology in the Medical Department of the 
University of Pennsylvania; President of the Medical Juris- 
prudence Society of Philadelphia ; Physician to St. Joseph's 
Hospital ; Corresponding Member of The New York Medico- 
legal Society. 2d Edition. Cloth, 3.00; Leather, 3.50 

Woodman and Tidy's Medical Jurisprudence and Toxi- 
cology. Chromo-Lithographic Plates and 116 Wood engravings. 

Cloth, 7.50; Leather, 8.50 

OBSTETRICS AND GYNECOLOGY. 

Byford. Diseases of Women, The Practice of Medicine and 
Surgery, as applied to the Diseases and Accidents Incident to 
Women. By W. H. Byford, a.m., m.d., Professor of Gynaecology 
in Rush Medical College and of Obstetrics in the Woman's Med- 
ical College, etc., and Henry T. Byford, m.d., Surgeon to the 
Woman's Hospital of Chicago ; Gynaecologist to St. Luke's 
Hospital, etc. Fourth Edition. Revised, Rewritten and En- 
larged. With 306 Illustrations, over 100 of which are original. 
Octavo. 832 pages. Cloth, 5.00 ; Leather, 6.00 

Cazeaux and Tarnier's Midwifery. With Appendix, by 
Munde. The Theory and Practice of Obstetrics-; including the 
Diseases of Pregnancy and Parturition, Obstetrical Operations, 
etc. By P. Cazeaux. Remodeled and rearranged, with revi- 
sions and additions, by S. Tarnier, m.d., Professor of Obstetrics 
and Diseases of Women and Children in the Faculty of Medicine 
of Paris. Eighth American, from the Eighth French and First 
Italian Edition. Edited by Robert J. Hess, m.d., Physician to 
the Northern Dispensary, Philadelphia, with an appendix by 
Paul F. Munde, m.d., Professor of Gynaecology at the N. Y. 
Polyclinic. Illustrated by Chromo-Lithographs, Lithographs, 
and other Full-page Plates, seven of which are beautifully colored, 
and numerous Wood Engravings. Students' Edition. One 
Vol., 8vo. Cloth, 5.00; Leather, 6.00 

Lewers' Diseases of Women. A Practical Text-Book. 139 
Illustrations. Second Edition. Cloth, 2.50 

Parvin's Winckel's Diseases of Women. Second Edition. 
Including a Section on Diseases of the Bladder and Urethra. 
150 Illustrations. Revised. See page 3. 

Cloth, 3.00; Leather, 3.50 

Morris. Compend of Gynaecology. Illustrated. In Press. 

WinckePs Obstetrics. A Text-book on Midwifery, includ- 
ing the Diseases of Childbed. By Dr. F. Winckel, Professor 
of Gynaecology, and Director of the Royal University Clinic for 
Women, in Munich. Authorized Translation, by J. Clifton 
Edgar, m.d., Lecturer on Obstetrics, University Medical Col- 
lege, New York, with nearly 200 handsome illustrations, the 
majority of which are original with this work. Octavo. 

Cloth, 6.00; Leather, 7.00 

Landis' Compend of Obstetrics. Illustrated. 4th edition, 
enlarged. Cloth, 1.00; Interleaved for Notes, 1.25 

jS^" See pages 2 to 5 for list of New Manuals. 



STUDENTS' TEXT-BOOKS AND MANUALS. 11 

Obstetrics and Gynecology : — Continued. 
Galabin's Midwifery. By A. Lewis Galabin, m.d., f.k.c.p. 
227 Illustrations. See page 3. Cloth, 3.00; Leather, 3.50 

Glisan's Modern Midwifery. 2d Edition. Cloth, 3.00 

Rigby's Obstetric Memoranda. 4th Edition. Cloth, .50 

Meadows' Manual of Midwifery. Including the Signs and 

Symptoms of Pregnancy, Obstetric Operations, Diseases of the 

Puerperal State, etc. 145 Illustrations. 494 pages. Cloth, 2.00 

Swayne's Obstetric Aphorisms. For the use of Students 

commencing Midwifery Practice. 8th Ed. i2mo. Cloth, 1.25 

PATHOLOGY. HISTOLOGY. BIOLOGY. 

Bowlby. Surgical Pathology and Morbid Anatomy, for 
Students. 135 Illustrations. i2mo. Cloth, 2.00 

Davis' Elementary Biology. Illustrated. Cloth, 4.00 

Gilliam's Essentials of Pathology. A Handbook for Students. 
47 Illustrations. i2mo. Cloth, 2.00 

*^.*The object of this book is to unfold to the beginner the funda- 
mentals of pathology in a plain, practical way, and by bringing 
them within easy comprehension to increase his interest in the study 
of the subject. 

Gibbes' Practical Histology and Pathology. Third Edition. 

Enlarged. i2mo. Cloth, 1.75 

Virchow's Post-Mortem Examinations. 2d Ed. Cloth, 1.00 

PHYSIOLOGY. 

Yeo's Physiology. Fourth Edition. The most Popular Stu- 
dents' Book. By Gerald F. Yeo, m.d., f.r.c.s., Professor of 
Physiology in King's College, London. Small Octavo. 758 
pages. 321 carefully printed Illustrations. With a Full 
Glossary and. Index. See Page 3. Cloth, 3.00; Leather, 3.50 

Brubaker's Compend of Physiology. Illustrated. Fifth 
Edition. Cloth, 1.00; Interleaved for Notes, 1.25 

Stirling. Practical Physiology, including Chemical and Ex- 
perimental Physiology. 142 Illustrations. Cloth, 2.25 

Kirke's Physiology. New 12th Ed. Thoroughly Revised and 
Enlarged. 502 Illustrations. Cloth, 4.00; Leather, 5.00 

Landois' Human Physiology. Including Histology and Micro- 
scopical Anatomy, and with special reference to Practical Medi- 
cine. Third Edition. Translated and Edited by Prof. Stirling. 
692 Illustrations. Cloth, 6.50; Leather, 7.50 

" With this Text-book at his command, no student could fail in 

his examination." — Lancet* 

Sanderson's Physiological Laboratory. Being Practical Ex- 
ercises for the Student. 350 Illustrations. 8vo. Cloth, 5.00 

Tyson's Cell Doctrine. Its History and Present State. Illus- 
trated. Second Edition. Cloth, 2.00 

4^=* See pages 14 and 15 for list of ? Quiz- Commends f 



12 STUDENTS' TEXT-BOOKS AND MANUALS. 



PRACTICE. 

Taylor. Practice of Medicine. A Manual. By Frederick 
Taylor, m.d., Physician to, and Lecturer on Medicine at, Guy's 
Hospital, London ; Physician to Evelina Hospital for Sick Chil- 
dren, and Examiner in Materia Medica and Pharmaceutical 
Chemistry, University of London. Cloth, 4.00 

Roberts' Practice. New Revised Edition. A Handbook 
of the Theory and Practice of Medicine. By Frederick T. 
Roberts, m.d. ; m.r.c.p., Professor of Clinical Medicine and 
Therapeutics in University College Hospital, London. Seventh 
Edition. Octavo. Cloth, 5.50 ; Sheep, 6.50 

Hughes. Compend of the Practice of Medicine. 4th Edi- 
tion. Two parts, each, Cloth, 1.00; Interleaved for Notes, 1.25 
Part i. — Continued, Eruptive and Periodical Fevers, Diseases 

of the Stomach, Intestines, Peritoneum, Biliary Passages, Liver, 

Kidneys, etc., and General Diseases, etc. 

Part ii. — Diseases of the Respiratory System, Circulatory 

System and Nervous System ; Diseases of the Blood, etc. 

Physician's Edition. Fourth Edition. Including a Section 
on Skin Diseases. With Index. 1 vol. Full Morocco, Gilt, 2.50 

Tanner's Index of Diseases, and Their Treatment. Cloth, 3.00 

PRESCRIPTION BOOKS. 

Wythe's Dose and Symptom Book. Containing the Doses 
and Uses of all the principal Articles of the Materia Medica, etc. 
Seventeenth Edition. Completely Revised and Rewritten. Just 
Ready. 32mo. Cloth, 1. 00; Pocket-book style, 1.25 

Pereira's Physician's Prescription Book. Containing Lists 
of Terms, Phrases, Contractions and Abbreviations used in 
Prescriptions Explanatory Notes, Grammatical Construction of 
Prescriptions, etc., etc. By Professor Jonathan Pereira, m.d. 
Sixteenth Edition. 32010. Cloth, 1. 00; Pocket-book style, 1.25 

PHARMACY. 

Stewart's Compend of Pharmacy. Based upon Remington's 
Text-Book of Pharmacy. Second Edition, Revised. 

Cloth., 1. 00 ; Interleaved for Notes, 1.25 

SKIN DISEASES. 

Anderson, (McCall) Skin Diseases. A complete Text-Book, 
with Colored Plates and numerous Wood Engravings. 8vo. 
Just Ready. Cloth, 4.50; Leather, 5.50 

Van Harlingen on Skin Diseases. A Handbook of the Dis- 
eases of the Skin, their Diagnosis and Treatment (arranged alpha- 
betically). By Arthur Van Harlingen, m.d., Clinical Lecturer 
on Dermatology, Jefferson Medical College; Prof, of Diseases of 
the Skin in the Philadelphia Polyclinic. 2d Edition. Enlarged. 
With colored and other plates and illustrations. i2mo. Cloth, 2.50 

Bulkley. The Skin in Health and Disease. By L. Duncan 
Bulkley, Physician to the N. Y. Hospital. Illus. Cloth, .50 

MBf See pages 2 to 5 for list of New Manuals. 



STUDENTS' TEXT-BOOKS AND MANUALS. 13 

SURGERY. 

Caird and Cathcart. Surgical Handbook for the use of 
Practitioners and Students. By F. Mitchell Caird, m b., 
f.r.c.s., and C. Walker Cathcart, m.b., f.r.c.s., Asst. Sur- 
geons Royal Infirmary. With over 200 Illustrations. 400 pages. 
Pocket size. Leather covers, 2.50 

Jacobson. Operations in Surgery. A Systematic Handbook 
for Physicians, Students and Hospital Surgeons. By W. H. A. 
Jacobson, b.a., Oxon. f.r.c.s. Eng. ; Ass't Surgeon Guy's Hos- 
pital ; Surgeon at Royal Hospital for Children and Women, etc. 
199 Illustrations. 1006 pages. 8vo. Cloth. 5.00; Leather, 6.00 

Heath's Minor Surgery, and Bandaging. Ninth Edition. 142 
Illustrations. 60 Formulae and Diet Lists. Cloth, 2.00 

Horwitz's Compend of Surgery, including Minor Surgery, 
Amputations, Fractures, Dislocations, Surgical Diseases, and the 
Latest Antiseptic Rules, etc., with Differential Diagnosis and 
Treatment. By Orville Horwitz, b.s., m.d., Demonstrator of 
Surgery, Jefferson Medical College. 3d edition. Enlarged and 
Rearranged. 91 Illustrations and 77 Formulae. 12m©. 

Cloth, 1. 00 ; Interleaved for the addition of Notes, 1.25 

Walsham. Manual of Practical Surgery. For Students and 
Physicians. By Wm. J. Walsham, m.d., f.r.c.s., Asst. Surg, 
to, and Dem. of Practical Surg, in, St. Bartholomew's Hospital, 
Surgeon to Metropolitan Free Hospital, London. With 236 
Engravings. See Page 2. Cloth, 3.00; Leather, 3.50 

URINE, URINARY ORGANS, ETC. 

Acton. The Reproductive Organs. In Childhood, Youth, 
Adult Life and Old Age. Seventh Edition. Cloth, 2.00 

Beale. Urinary and Renal Diseases and Calculous Disorders. 
Hints on Diagnosis and Treatment. i2mo. Cloth, 1.75 

Holland. The Urine, and Common Poisons and The 
Milk. Chemical and Microscopical, for Laboratory Use. Illus- 
trated. Third Edition. i2mo. Interleaved. Cloth, 1.00 

Ralfe. Kidney Diseases and Urinary Derangements. 42 Illus- 
trations. i2mo. 572 pages. Cloth, 2.75 

Legg. On the Urine. A Practical Guide. 6th Ed. Cloth, .75 

Marshall and Smith. On the Urine. The Chemical Analysis of 
the Urine. By John Marshall, m.d., Chemical Laboratory, Univ. 
of Penna ; and Prof. E. F. Smith, ph.d. Col. Plates. Cloth, 1.00 

Thompson. Diseases of the Urinary Organs. Eighth 
London Edition. Illustrated. Cloth, 3.50 

Tyson. On the Urine. A Practical Guide to the Examination 
of Urine. With Colored Plates and Wood Engravings. 6th Ed. 
Enlarged, iamo. Cloth, 1.50 

Bright's Disease and Diabetes. Illus. Cloth, 3.50 

Van Nuys, Urine Analysis. Illus. Cloth, 2.00 

VENEREAL DISEASES. 

Hill and Cooper. Student's Manual of Venereal Diseases, 
with Formulae. Fourth Edition. i2mo. Cloth, 1.00 

Durkee. On Gonorrhoea and Syphilis. Illus. Cloth, 3.50 
4®=* See pages 14 and 15 for list of ? Quiz- Comp ends ? 



NEW AND REVISED EDITIONS. 

PQUIZ-COMPENDS? 

The Best Compends for Students' Use 
in the Quiz Class, and when Pre- 
paring for Examinations. 

Compiled in accordance with the latest teachings of promi- 
nent lecturers and the most popular Text-books. 

They form a most complete, practical and exhaustive 
set of manuals, containing information nowhere else col- 
lected in such a condensed, practical shape. Thoroughly 
tip to the times in every respect, containing many new 
prescriptions and formulae, and over two hundred and 
fifty illustrations, many of which have been drawn and 
engraved specially for this series. The authors have had 
large experience as quiz-masters and attaches of colleges, 
with exceptional opportunities for noting the most recent 
advances and methods. 

Cloth, each $1.00. Interleaved for Notes, $1.25. 
No. 1. HUMAN ANATOMY, ''Based upon Gray." Fourth 
Edition, including Visceral Anatomy, formerly published 
separately. Over 100 Illustrations. By Samuel O. L. 
Potter, m.a., m.d., late A. A. Surgeon U. S. Army. Professor 
of Practice, Cooper Medical College, San Francisco. 
Nos. 2 and 3. PRACTICE OF MEDICINE. Fourth Edi- 
tion. By Daniel E. Hughes, m.d., Demonstrator of Clinical 
Medicine in Jefferson Medical College, Philadelphia. In two parts. 
Part I. — Continued, Eruptive and Periodical Fevers, Disease* 
of the Stomach, Intestines, Peritoneum, Biliary Passages, Liver, 
Kidneys, etc. (including Tests for Urine), General Diseases, etc. 

Part II. — Diseases of the Respiratory System (including Phy- 
sical Diagnosis), Circulatory System and Nervous System; Dis- 
eases of the Blood, etc. 

*** These little books can be regarded as a full set of notes upon • 
the Practice of Medicine, containing the Synonyms, Definitions, 
Causes, Symptoms, Prognosis, Diagnosis, Treatment, etc., of each 
disease, and including a number of prescriptions hitherto unpub- 
lished. 

No. 4. PHYSIOLOGY, including Embryology. Fifth 
Edition. By Albert P. Brubaker, m.d., Prof, of Physiology, 
Penn'a College of Dental Surgery; Demonstrator of Physiology 
in Jefferson Medical College, Philadelphia. Revised, Enlarged 
and Illustrated. 
No. 5. OBSTETRICS. Illustrated. Fourth Edition. By 
Henry G. Landis, m.d., Prof, of Obstetrics and Diseases of 
Women, in Starling Medical College, Columbus, O. Revised 
Edition. New Illustrations. 



BLAKISTON'S ? QUIZ-COMPENDS ? 

Continued. 

Bound in Cloth, $1.00. Interleaved, for Notes, $1.25 

No. 6. MATERIA MEDICA, THERAPEUTICS AND 
PRESCRIPTION WRITING. Fifth Revised Edition. 

With especial Reference to the Physiological Action of Drugs, 
and a complete article on Prescription Writing. Based on the 
Last Revision of the U. S. Pharmacopoeia, and including many 
unofficinal remedies. By Samuel O. L. Potter, m.a., m.d., 
late A. A. Surg. U. S. Army; Prof, of Practice, Cooper Medical 
College, San Francisco. Improved and Enlarged, with Index. 

No. 7. GYNECOLOGY. A Compend of Diseases of Women. 
By Henry Morris, m.d., Demonstrator of Obstetrics, Jefferson 
Medical College, Philadelphia. 

No. 8. DISEASES OF THE EYE AND REFRACTION, 

including Treatment and Surgery. By L. Webster Fox, m.d., 
Chief Clinical Assistant Ophthalmological Dept., Jefferson Med- 
ical College, etc., and Geo. M. Gould, m.d. 71 Illustrations, 39 
Formulae. Second Enlarged and Improved Edition. Index. 

No. 9. SURGERY. Illustrated. Third Edition. Including 
Fractures, Wounds, Dislocations, Sprains, Amputations and 
other operations; Inflammation, Suppuration, Ulcers, Syphilis, 
Tumors, Shock, etc. Diseases of the Spine, Ear, Bladder, Tes- 
ticles, Anus, and other Surgical Diseases. By Orville Horwitz, 
a.m., m.d., Demonstrator of Surgery, Jefferson Medical Col- 
lege. Revised and Enlarged. 77 Formulas and 91 Illustrations. 

No. 10. CHEMISTRY. Inorganic and Organic. For Medical 
and Dental Students. Including Urinary Analysis and Medical 
Chemistry. By Henry Leffmann, m.d., Prof", of Chemistry in 
Penn'a College of Dental Surgery, Phila. Third Edition, Revised 
and Rewritten, with Index. 

No. 11. PHARMACY. Based upon ,( Remington's Text-book 
of Pharmacy.' ' By F. E. Stewart, m.d., ph. g., Quiz-Master 
at Philadelphia College of Pharmacy. Second Edition, Revised. 

No. 12. VETERINARY ANATOMY AND PHYSIOL- 
OGY. 29 Illustrations. By Wm. R. Ballou, m.d., Prof, of 
Equine Anatomy at N. Y. College of Veterinary Surgeons. 

No. 13. DISEASES OF CHILDREN. By Dr. Marcus P. 
Hatfield, Prof, of Diseases of Children, Chicago Medical 
College. 

Bound in Cloth, $1. Interleaved, for the Addition of Notes, $1.25. 



These books are constantly revised to keep up with 
the latest teachings and discoveries ', so that they contain 
all the new methods and principles. No series of books 
are so complete in detail, concise in language, or so well 
printed and bound. Each one forms a complete set of 
notes upon the subject under consideration. 

Descriptive Circular Free. 



NOW READY. 



A NEW 

MEDICAL 

DICTIONARY 

BY GEORGE M. GOULD, 

Ophthalmic Surgeon, Philadelphia Hospital, etc. 



AN ENTIRELY NEW BOOK. 
Based On Recent Medical Literature. 



Small Octavo. 520 Pages. Handsomely Printed. 

Bound in Half Dark Leather, $3.25. 

Half Morocco, Thumb Index, $4.25. 



SEND FOR SPECIAL CIRCULAR. 



